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Prof. Dr.-Ing. Günther Benstetter

Mikroelektronik und Mikrosystemtechnik
Elektronische Bauelemente
Materialwissenschaften und angewandte Festkörperphysik
Qualitätssicherung und Zuverlässigkeitsanalytik

Fakultät Elektrotechnik und Medientechnik

Professorinnen und Professoren

Studiendekan

E 208

0991/3615-513

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Publikationen

Sortierung:

Vortrag

Günther Benstetter
et al.

Vergleich von Kalibrierungsmethoden für Laserinduzierte Fluoreszenz (LIF).

Greifswald 1993.

(1993)

Vortrag

Günther Benstetter

Grundlagen der Laserinduzierten Fluoreszenz.

Technische Universität.

München 1994.

(1994)

Vortrag

Günther Benstetter
et al.

Laserinduzierte Fluoreszenz am expandierenden Vakuumbogenplasma.

Erlangen März 1994.

(1994)

Vortrag

Günther Benstetter

Abscheidung dünner Metallschichten durch eine neuartige Plasmaentladung.

Technische Universität.

München Mai 1994.

(1994)

Monographie

Günther Benstetter

Laserstreuung und Entladungsdiagnostik am Beschichtungsplasma eines anodischen Vakuumbogens.

Düsseldorf: VDI-Verlag Nr. 336)

(1995)

Beitrag in Sammelwerk/Tagungsband

Günther Benstetter
et al.

Failure Analysis of DRAM Storage Node Trench Capacitors for 0.35-Micron and Follow-On Technologies Using the Focused Ion Beam for Electrical and Physical Analysis.

pg. 401-407

(1996)

Zeitschriftenartikel

H. Göbel
Günther Benstetter

Schnittstellen für schnelle Halbleiterspeicher.

In: Nachrichtentechnische Zeitschrift (ntz) (vol. 49) , pg. 28-33

(1996)

Zeitschriftenartikel

Günther Benstetter

Anodischer Niedervoltbogen als Beschichtungsplasma.

In: Journal für Oberflächentechnik (JOT) , pg. 13-16

(1996)

Zeitschriftenartikel

Günther Benstetter

Experimental Observations of Steady Anodic Vacuum Arcs with Hot Cathode.

In: IEEE Transactions on Plasma Science (vol. 24) , pg. 1389-1393

(1996)

Abstract anzeigen

Stationary plasma discharges have been investigated in a high vacuum ambient (background gas pressure <10-2 Pa), with an externally heated cathode and a consumable hot evaporating anode. With various anode materials like chromium or copper, and electrode separations between 0.5 and 3 mm, the nonself-sustained discharge operates with DC arc currents in the range of 220 A. The waveform of the arc voltage is strongly influenced by the magnetic field of the cathode heating current, and arc voltages between a minimum of 3 V and a maximum exceeding 100 V have been observed. The voltage-current characteristics (VCC) and the influence of the electrode separation have been measured separately for the minimum and the maximum of the arc voltages and show a different behavior. The metal plasma expands into the ambient vacuum toward the walls of the vacuum vessel and offers a macroparticle free deposition source of thin films. The arc voltage can be varied by external manipulations of the arc discharge, and the mean ion energy of the expanding metal plasma shows a linear dependence of the mean arc voltage

Beitrag in Sammelwerk/Tagungsband

Günther Benstetter
et al.

Reliability and Failure Analysis of 64 & 256 Mb DRAM Trench Capacitors.

München: VDE-Verlag pg. 251-258

(1997)

Zeitschriftenartikel

Günther Benstetter
R. Vollertsen

Zuverlässigkeitsanalysen an Sub- Mikrometer CMOS Transistoren.

In: QZ - Qualität und Zuverlässigkeit , pg. 1264-1267

(1997)

Zeitschriftenartikel

Günther Benstetter
H. Göbel

Zuverlässigkeitsherausforderungen dünner Dielektrika in Sub-Mikrometer ICs.

In: F&M Feinwerktechnik Mikrotechnik Mikroelektronik , pg. 127-132

(1997)

Beitrag in Sammelwerk/Tagungsband

H. Göbel
Günther Benstetter

Schnittstellen für schnelle Halbleiterspeicher.

Berlin; Offenbach: VDE-Verlag

(1997)

Zeitschriftenartikel

Günther Benstetter
A. Glasow

IC-Ausfälle durch Elektromigration: Zuverlässigkeit metallischer Leitbahnen in ULSI-Technologien.

In: F&M Feinwerktechnik Mikrotechnik Mikroelektronik

(1999)

Vortrag

Günther Benstetter

Technologie-Zuverlässigkeit von Sub-Mikrometer-ICs.

Technische Universität.

München 07.02.2000.

(2000)

Zeitschriftenartikel

P. Awakowicz
R. Schwefel
P. Scheubert
Günther Benstetter

Deposition of a-C:H Films with an ECWR-Reactor at 27 MHz: Plasma Diagnostics and Correlation to Film Properties.

In: Surface & Coatings Technology , pg. 342-347

(2001)

DOI: 10.1016/S0257-8972(01)01313-5

Abstract anzeigen

For the first time, an electron–cyclotron-wave resonance (ECWR) source was used to deposit thin amorphous hydrocarbon (a-C:H) films. The deposition experiments have been supported by intensive plasma diagnostics with Langmuir probe (LP) measurements and energy mass spectrometry (EMS). The LP-investigations yielded a set of external parameters for homogeneously grown hard films at deposition rates of approximately 1.5 μm/h. By calibrating the EMS-system for particle number densities of stabile hydrocarbons and by using an appropriate fit-formula to evaluate absolute ion flux densities, the growth rates were in good agreement with predictions of the ‘thermally activated re-etching’-model (TR-model).

Vortrag

Werner Frammelsberger
Günther Benstetter
R. Stamp
J. Kiely

Combined AFM Methods to Improve Reliability Investigations of Thin Oxides. Final Report.

Lake Tahoe, CA, USA 2002.

(2002)

Zeitschriftenartikel

Günther Benstetter
M. Ruprecht
D. Hunt

A review of ULSI failure analysis techniques for DRAMs , Part I: defect localization and verification. Introductory Invited Paper.

In: Microelectronics Reliability (vol. 42) , pg. 307-316

(2002)

DOI: 10.1016/S0026-2714(02)00002-1

Abstract anzeigen

In this paper defect localization and verification procedures for ULSI DRAMs are described. The analytical process can be grouped into three subsequent phases: component based, die based and local techniques. Beginning with non-destructive localization methods on component level, such as X-ray and scanning acoustic microscopy (SAM), subsequent depackaging of the component enables more extensive electrical probing and physical defect localization at die level. The techniques applied at that level are liquid crystal, optical beam-induced current (OBIC), photo emission microscopy (PEM) and focused ion beam (FIB) to narrow down the failing area. The final fail location is determined after subsequent unlayering steps. Electrical microprobing and FIB techniques are utilized to verify the precisely localized fail within the previously determined area.

Vortrag

Günther Benstetter
Werner Frammelsberger
T. Schweinböck
R. Stamp
J. Kiely

Conducting Atomic Force Microscopy Studies for Reliability Evaluation of Ultrathin SiO2 Films. Final Report.

Lake Tahoe, CA, USA 2002.

(2002)

Vortrag

Günther Benstetter
R. Schmidt
S. Ascher
M. Kerber
Johannes Grabmeier
A. Huber

Evaluation of thin oxide reliability by means of wafer level stress-testing.

Prien am Chiemsee April 2002.

(2002)

Vortrag

D. Liu
Günther Benstetter
Y. Liu
T. Ma

Surface Roughness and Mechanical Properties of a-C:H Films Prepared by Low-pressure Dielectric Barrier Discharge.

Garmisch-Partenkirchen 9.-13.9.2002.

(2002)

Vortrag

D. Liu
Günther Benstetter
Edgar Lodermeier

Comparison of Nanoscale Scratch and Wear Resistance of a-C:H, a-C:N and ta-C Fillms.

Garmisch-Partenkirchen 9.-13.9.2002.

(2002)

Beitrag in Sammelwerk/Tagungsband

Werner Frammelsberger
Günther Benstetter
T. Schweinböck
R. Stamp
J. Kiely

Advanced Analysis of Thin and Ultrathin SiO2/Si Interfaces with Combined Atomic Force Microscopy Methods.

pg. 406-412

(2003)

Zeitschriftenartikel

D. Liu
Günther Benstetter
Y. Liu
X. Xang
S. Yu
T. Ma

Medium- to high-pressure plasma deposition of a-C:H films by dielectric barrier discharge.

In: New Diamond and Frontier Carbon Technology (vol. 13) , pg. 191-206

(2003)

Zeitschriftenartikel

D. Liu
Günther Benstetter
Edgar Lodermeier
J. Vancea

Influence of the incident angle of energetic carbon ions on the properties of tetrahedral amorphous carbon (ta-C) films.

In: Journal of Vacuum Science & Technology A (vol. 21) , pg. 1655-1670

(2003)

DOI: 10.1116/1.1597888

Abstract anzeigen

Tetrahedral amorphouscarbon (ta-C) films have been grown on Ar+-beam-cleaned silicon substrates by changing the incident angle of energetic carbon ions produced in the plasma of pulsed cathodic vacuum arc discharge. Their surface roughness, deposition rate, composition, and mechanical and frictional properties as a function of the incident angle of energetic carbon ions were reported. The substrate holder can be rotated, and so an angle of deposition was defined as the angle of ion flux with respect to the substrate surface. While the deposition angle is varied from 20° to 59°, the root-mean-square (rms) roughness decreases from 0.5 to 0.1 nm, then it turns to increase at a slow rate when the deposition angle is over 77°. The variation correlates well with the one of hardness with the deposition angle and the films with lower rms roughness exhibit the higher hardness. The soft graphite-like surface layers existing at the surfaces of these films were revealed by atomic force microscopy-based nanowear tests and their thickness increases from 0.35 to 2.9 nm with the deposition angle decreasing from 90° to 30°. The soft surface layer thickness can have a great effect on the sp3 contents measured by x-ray photoelectron spectra. Nanoscale friction coefficient measurements were performed from lateral force microscopy by using a V-shaped Si3N4 cantilever. The low friction coefficients (0.076–0.093) of ta-C films can be attributed to their graphite-like surface structure. The implications of these results on the mechanisms proposed for the film formation were discussed.

Zeitschriftenartikel

M. Ruprecht
Günther Benstetter
D. Hunt

A review of ULSI failure analysis techniques for DRAMs , Part II: defect isolation and visualization. Introductory Invited Paper.

In: Microelectronics Reliability (vol. 43) , pg. 17-41

(2003)

DOI: 10.1016/S0026-2714(02)00295-0

Abstract anzeigen

In this paper the basic techniques for defect isolation and visualization used in physical failure analysis of trench technique dynamic random access memories (DRAMs) are reviewed. The methods described are state-of-the-art for DRAM failure analysis down to 0.14 μm feature size and beyond. In addition to defect isolation and defect visualization from the front side of a die, the backside preparation approach is reviewed. Beginning with basic sample preparation techniques including mechanical polishing, wet and dry etching and focused ion beam (FIB) applications advantages and disadvantages of various techniques are discussed. In the second section of the paper different types of optical microscopes are covered as well as scanning and transmission electron microscopes. The imaging capabilities of the FIB systems are included in this section. Finally, some applications of scanning probe techniques especially for dopant measurements and thin oxide characterization are described.

Zeitschriftenartikel

D. Liu
Günther Benstetter
Edgar Lodermeier
X. Chen
J. Ding
Y. Liu
J. Zhang
T. Ma

Surface and structural properties of ultrathin diamond-like carbon coatings.

In: Diamond and Related Materials (vol. 12) , pg. 1594-1600

(2003)

DOI: 10.1016/S0925-9635(03)00248-6

Abstract anzeigen

Nanoscale wear resistance, friction, and electrical conduction tests using atomic force microscope (AFM) have been conducted on ultrathin diamond-like carbon (DLC) coatings, including tetrahedral amorphous carbon (ta-C) deposited using pulsed cathodic arc (PCA) and filtered-PCA, and hydrogenated amorphous carbon (a-C:H) deposited using electron cyclotron resonance—chemical vapor deposition (ECR-CVD). The low-resistant layers at the surfaces of these thin DLC coatings were revealed by AFM-based nanowear tests. Their thickness is mainly determined by the deposition methods and does not show an obvious variation with the coating thickness decreasing from tens of nm to a few nm. The ∼3 nm ta-C coatings from PCA and filtered-PCA deposition were found to have the stable bulk structure beneath the thin (0.3–0.95 nm) surface layers. The ∼3 nm a-C:H coating from ECR-CVD had the extremely low load-carrying capacity and exhibited the evidence of coating delamination, which can be related to the thicker (1.5±0.1 nm) soft surface layers of a-C:H coatings. The results from conducting-AFM measurements indicate that a-C:H coatings have H and sp3 C enrichment surface layers while the soft surface layers of ta-C coatings have graphite-like structure. The nanoscale friction coefficients of these thin ta-C and a-C:H coatings were compared by AFM-based lateral force microscope. The lower friction coefficient of ta-C coatings can be attributed to the existence of graphite-like surface structure.

Zeitschriftenartikel

Werner Frammelsberger
Günther Benstetter
T. Schweinböck
R. Stamp
J. Kiely

Characterization of thin and ultrathin SiO2 films and SiO2/Si interfaces with combined conducting and topographic atomic force microscopy.

In: Microelectronics Reliability (vol. 43) , pg. 1465-1470

(2003)

DOI: 10.1016/S0026-2714(03)00260-9

Zeitschriftenartikel

D. Li
Günther Benstetter
Edgar Lodermeier
I. Akula
I. Dudarchyk
Y. Liu
T. Ma

SPM investigation of diamond-like carbon and carbon nitride films.

In: Surface & Coatings Technology (vol. 172) , pg. 194-203

(2003)

DOI: 10.1016/S0257-8972(03)00338-4

Abstract anzeigen

Scanning probe microscopy was used to evaluate and compare the surface roughness, mechanical and tribological properties of hydrogenated (a-C:H) and tetrahedral (ta-C) diamond-like carbon (DLC) and amorphous carbon nitride (a-C:N) films. Compared to the a-C:H and a-C:N films, the ta-C films exhibit the lowest surface roughness. The soft surface layers of DLC and a-C:N films were revealed by nanowear tests and their thickness varies over the range of 0.2 to 4.1 nm. The nanoscale friction coefficient measurements from lateral force microscopy shows that these films have obviously different friction coefficients. The lower friction coefficients of ta-C and a-C:N films can be attributed to the existence of soft graphite-like surface structure. We proposed the deposition processes of DLC and a-C:N films, where their surface roughness, structure and mechanical properties were associated with the vapor plasma particle energy distribution.

Zeitschriftenartikel

D. Liu
Günther Benstetter
Y. Liu
T. Ma

Surface roughness, scratch resistance and tribological properties of hydrogenated amorphous carbon coatings prepared by low-pressure dielectric barrier discharge.

In: Surface & Coatings Technology (vol. 174-175) , pg. 310-315

(2003)

DOI: 10.1016/S0257-8972(03)00649-2

Abstract anzeigen

In this study, we explored the surface roughness, scratch resistance and tribological properties of hydrogenated amorphous carbon (a-C:H) coatings deposited on silicon substrates from low-pressure dielectric barrier discharge (DBD) plasmas of CH4 by using an atomic force microscope (AFM), AFM-based scratch testing technique and lateral force microscope. The AFM and scratch measurements show that the surface roughness and scratch resistance of these a-C:H coatings strongly depend on the Pd value (the product of CH4 pressure P, and discharge gas spacing d) and the a-C:H coatings deposited at suitable Pd value (typically 350 Pa mm) exhibit lower surface roughness and better scratch resistance. The a-C:H coatings deposited at the Pd value of 350–1750 Pa mm have the typical friction coefficient of approximately 0.13. The lower friction coefficient (0.11) of the a-C:H coating deposited at the smaller Pd value of 245 Pa mm can be associated with its graphite-like surface structure. The results indicate the coating structure changes from the one of graphite-like to diamond-like to polymer-like with the Pd value increasing from 245 to 1750 Pa mm. The relationship between the measured coating properties and the DBD deposition processes was presented.

Vortrag

Günther Benstetter
Werner Frammelsberger
et al.

UV unterstützter thermischer Oxidationsofen. Präsentation, Kategorie Patente.

Würzburg 2003.

(2003)

Zeitschriftenartikel

D. Liu
Günther Benstetter
Werner Frammelsberger

The effect of the surface layer of tetrahedral amorphous carbon films on their tribological and electron emission properties investigated by atomic force microscopy.

In: Applied Physics Letters (vol. 82) , pg. 3898-3900

(2003)

DOI: 10.1063/1.1581367

Abstract anzeigen

The nanowear resistance, tribological, and field emissionproperties of tetrahedral amorphous carbon (ta-C) films have been analyzed by atomic force microscope (AFM)-based wear testing technique, lateral force microscope, and conducting AFM. The ta-C films grown by filtered pulsed cathodic arc discharge were found to have soft surface layers, thick, which contribute to an improvement of their field emissionproperties. The low friction coefficient between the nanotip and film surface is correlated to one or two graphite-like atomic layers at the ta-C film surfaces. The analysis of Fowler–Nordheim tunneling currents indicates the formation of filament-like emission channels in amorphous carbon films.

Vortrag

Werner Frammelsberger
Günther Benstetter
T. Schweinböck
R. Stamp
J. Kiely
Peter Breitschopf

Atomic Force Microscopy Studies of Thin and Ultra-thin SiO2 Films. Final Report.

München 2003.

(2003)

Zeitschriftenartikel

D. Liu
Günther Benstetter
Edgar Lodermeier

Surface roughness, mechanical and tribological properties of ultrathin tetrahedral amorphous carbon coatings from atomic force measurements.

In: Thin Solid Films (vol. 436) , pg. 244-249

(2003)

DOI: 10.1016/S0040-6090(03)00592-3

Abstract anzeigen

Atomic force microscope (AFM), lateral force microscope and AFM-based scratch and wear testing techniques were used to evaluate and compare the surface roughness, tribological and mechanical properties of thin (2.7–43 nm) tetrahedral amorphous carbon coatings prepared by pulsed cathodic arc discharge. It was found that surface roughness of ultrathin (2–8 nm) coatings was mainly determined by the roughness of the Si substrate and their average density strongly depended on their thickness. Poor friction, mechanical properties of thinner (2.7–15 nm) coatings can be associated with their low average density. The dense coatings (>15 nm) had lower friction coefficient, better scratch and wear resistance properties that were independent of their thickness. It appears that the over 15-nm coatings studied are feasible for some wear-resistant and tribological applications.

Vortrag

D. Liu
Günther Benstetter
Edgar Lodermeier
J. Vancea

Influence of the incident angle of energetic carbon ions on the properties of tetrahedral amorphous carbon (ta-C) films.

Taormina, Italien 22.-27.06.2003.

(2003)

Vortrag

Werner Frammelsberger
Günther Benstetter
R. Stamp
J. Kiely

Characterization of thin and ultrathin SiO2 films and SiO2/Si interfaces with combined conducting and topographic atomic force microscopy.

Arcachon, Frankreich 06.-10.10.2003.

(2003)

Vortrag

Werner Frammelsberger
Günther Benstetter
T. Schweinböck
R. Stamp
J. Kiely

Advanced Analysis of Thin and Ultrathin SiO2/Si Interfaces with Combined Atomic Force Microscopy Methods.

Santa Clara, CA, USA November 2003.

(2003)

Vortrag

Werner Frammelsberger
Günther Benstetter

Verfahren der Rastersondenmikroskopie. Präsentation, Kategorie Patente.

Würzburg November 2003.

(2003)

Vortrag

Günther Benstetter

Reliability Analysis of Integrated Circuits in Deep Sub-Micron Technology.

Dalian University of Technology, Key-Labs.

Dalian, China 17.11.2003.

(2003)

Vortrag

Günther Benstetter

Failure Analysis of Deep Sub-Micron Semiconductor Structures.

Dalian University of Technology, Key-Labs.

Dalian, China 17.11.2003.

(2003)

Vortrag

Werner Frammelsberger
Günther Benstetter
et al.

Atomic Force Microscopy Studies of Thin and Ultra-Thin SiO2 Films and Interfaces.

Dalian University of Technology, Key-Labs.

Dalian, China 19.11.2003.

(2003)

Vortrag

Werner Frammelsberger
Günther Benstetter

Atomic Force Microscopy Studies of Thin and Ultra-Thin SiO2 Films and Interfaces.

Chinese Academy of Science, Institute of Microelectronics.

Peking, China 24.11.2003.

(2003)

Vortrag

Werner Frammelsberger
Günther Benstetter

Failure Analysis of Deep Sub-Micron Semiconductor Structures.

Chinese Academy of Science, Institute of Microelectronics.

Peking, China 24.11.2003.

(2003)

Vortrag

Günther Benstetter

Failure Analysis of Deep Sub-Micron Semiconductor Structures.

Chinese Academy of Science, Institute of Microelectronics.

Peking, China 24.11.2003.

(2003)

Vortrag

Günther Benstetter

Reliability Analysis of Integrated Circuits in Deep Sub-Micron Technology.

Chinese Academy of Science, Institute of Microelectronics.

Peking, China 24.11.2003.

(2003)

Vortrag

Werner Frammelsberger
Günther Benstetter

Failure Analysis of Deep Sub-Micron Semiconductor Structures, Presentation held at: Dalian University of Technology.

Chinese Academy of Science, Institute of Microelectronics.

Peking, China 24.11.2003.

(2003)

Vortrag

Werner Frammelsberger
Günther Benstetter

Reliability Analysis of Integrated Circuits in Deep Sub-Micron Technology.

Chinese Academy of Science, Institute of Microelectronics.

Peking, China 24.11.2003.

(2003)

Zeitschriftenartikel

Werner Frammelsberger
Günther Benstetter
R. Stamp
J. Kiely
T. Schweinböck

Simplified tunnelling current calculation for MOS structures with ultra-thin oxides for Conductive Atomic Force Microscopy investigations.

In: Materials Science & Engineering B (vol. 116) , pg. 168-174

(2004)

DOI: 10.1016/j.mseb.2004.09.027

Abstract anzeigen

As charge tunnelling through thin and ultra-thin silicon dioxide layers is regarded as the driving force for MOS device degradation the determination and characterisation of electrically week spots is of paramount importance for device reliability and failure analysis. Conductive atomic force microscopy (C-AFM) is able to address this issue with a spatial resolution smaller than the expected breakdown spot. For the determination of the electrically active oxide thickness in practice an easy to use model with sufficient accuracy and which is largely independent of the oxide thickness is required. In this work a simplified method is presented that meets these demands. The electrically active oxide thickness is determined by matching of C-AFM voltage–current curves and a tunnelling current model, which is based on an analytical tunnelling current approximation. The model holds for both the Fowler–Nordheim tunnelling and the direct tunnelling regime with one single tunnelling parameter set. The results show good agreement with macroscopic measurements for gate voltages larger than approximately 0.5–1 V, and with microscopic C-AFM measurements. For this reason arbitrary oxides in the DT and the FNT regime may be analysed with high lateral resolution by C-AFM, without the need of a preselection of the tunnelling regime to be addressed.

Zeitschriftenartikel

T. Schweinböck
S. Schömann
D. Alvarez
M. Buzzu
Günther Benstetter
Werner Frammelsberger
Peter Breitschopf

New Trends in the application of scanning probe techniques in failure analysis.

In: Microelectronics Reliability (vol. 44) , pg. 1541-1546

(2004)

DOI: 10.1016/j.microrel.2004.07.037

Beitrag in Sammelwerk/Tagungsband

Günther Benstetter
Werner Frammelsberger

Raster Sondenmikroskopie in der Mikro- und Nanoelektronik.

pg. 12-16

(2004)

Zeitschriftenartikel

Günther Benstetter
Peter Breitschopf
Werner Frammelsberger
Heiko Ranzinger
P. Reislhuber
T. Schweinböck

AFM-based scanning capacitance techniques for deep sub-micron semiconductor failure analysis.

In: Microelectronics Reliability (vol. 44) , pg. 1615-1619

(2004)

DOI: 10.1016/j.microrel.2004.07.079

Vortrag

T. Schweinböck
S. Schömann
D. Alvarez
M. Buzzu
Günther Benstetter
Werner Frammelsberger
Peter Breitschopf

New Trends in the application of scanning probe techniques in failure analysis.

Zürich, Schweiz 2004.

(2004)

Vortrag

Günther Benstetter
Werner Frammelsberger
D. Liu
Peter Breitschopf

Failure analysis of deep sub-micron semiconductor structures and thin films with atomic force microscopy methods.

Lissabon, Portugal 2004.

(2004)

Zeitschriftenartikel

D. Liu
Günther Benstetter
Edgar Lodermeier
J. Zhang
Y. Liu
J. Vancea

Filtered pulsed carbon cathodic arc: plasma and amorphous carbon properties.

In: Journal of Applied Physics (vol. 95) , pg. 7624-7631

(2004)

DOI: 10.1063/1.1753081

Abstract anzeigen

The carbonplasma ion energies produced by the filtered pulsed cathodic arc discharge method were measured as a function of filter inductance. The energy determination is based on the electro-optical time-of-flight method. The average ion energies of the pulsed ion beams were found to depend upon the rise time and duration of pulsed arc currents, which suggests that a gain of ion kinetic energy mainly arises from the electric plasma field from the ambipolar expansion of both electrons and ions, and an electron drag force because of the high expansion velocity of the electrons. The tetrahedral amorphous carbon (ta-C) films with a sp3 fraction of ∼70% were deposited on silicon substrates at the average ion energies of >6 eV in the highly ionized plasmas. The ta-C films were found to be covered with a few graphitelike atomic layers. The surfaceproperties of ultrathin carbonfilms, such as nanoscale friction coefficients, surface layer thickness, and silicon contents were strongly dependent on the ion energies. The growth of amorphous carbonfilms was explained in terms of the thermal spike migration of surfacecarbon atoms. In terms of this model, the thermal spike provides the energy required to release surface atoms from their metastable positions and leads to the formation of the sp3 bonded carbon on a sp3 bonded matrix. The experimental results indicate that the low-energy (<3 eV)carbon ions have insufficient energies to cause the rearrangement reaction within the film and they form graphitelike structures at filmsurface.

Zeitschriftenartikel

D. Liu
Günther Benstetter
W. Wang
J. Zhang

Effect of pressure on the deposition of hydrogen-free amorphous carbon and carbon nitride films by the pulsed cathodic arc discharge method.

In: Journal of Vacuum Science & Technology A (vol. 22) , pg. 2329

(2004)

DOI: 10.1116/1.1798691

Abstract anzeigen

Hydrogen-free amorphous carbon and carbon nitride films were deposited using the pulsed cathodic arc discharge at different argon and nitrogen pressures. The surface and mechanical properties of these films were found to strongly depend on the gas pressure. The tetrahedral amorphous carbon and hard films with smooth surfaces (rms roughness: ) were prepared at lower gas pressures. Incorporation of an increasing amount of nitrogen in films caused a decrease in filmhardness. All the films were covered with the thin graphite-like surface layers. The filmhardness was correlated to the soft surface layer thickness, and the films with thinner surface layers exhibit higher hardness. The mean energies of pulsed plasma beams were measured as the functions of argon and nitrogen pressures. The mean energies of plasma beams decrease in an exponential fashion with increasing gas pressure due to the carbon ion collisions with the neutral gas species. The effects of mean energies of deposited species on the filmdeposition were explained in terms of the thermal spike migration of surface atoms. The formation of graphite-like surface layers is associated with the low-energy deposition process. The low-energy species diffusing on filmsurface lead to the formation of graphite-like films with plenty of grains. The higher-energy species may produce the strong thermal spike at filmsurface, and contribute to the formation of bonded structure at a bonded matrix.

Beitrag in Sammelwerk/Tagungsband

Günther Benstetter
Werner Frammelsberger

Raster Sondenmikroskopie in der Mikro- und Nanoelektronik.

In:
Bayerisches Staatsministerium für Wirtschaft, Infrastruktur, Verkehr und Technologie
Bayerisches Staatsministerium für Wirtschaft, Infrastruktur, Verkehr und Technologie

pg. 12-16

(2004)

Vortrag

Günther Benstetter
Peter Breitschopf
Werner Frammelsberger
Heiko Ranzinger
P. Reislhuber
T. Schweinböck

AFM-based scanning capacitance techniques for deep sub-micron semiconductor failure analysis.

Zürich, Schweiz 2004.

(2004)

Vortrag

D. Liu
Günther Benstetter
Edgar Lodermeier

Surface properties and growth of diamond-like carbon films prepared using CVD and PVD methods.

Strasbourg, Frankreich 24.-28.5.2004.

(2004)

Vortrag

D. Liu
Günther Benstetter

Comparison of bulk and surface structure in a-C:H films.

Garmisch-Partenkirchen 13.-17.9.2004.

(2004)

Zeitschriftenartikel

Y. Liu
J. Zhang
D. Liu
T. Ma
Günther Benstetter

A triangular section magnetic solenoid filter for removal of macro- and nano-particles from pulsed graphite cathodic vacuum arc plasmas.

In: Surface & Coatings Technology (vol. 200) , pg. 2243-2248

(2005)

DOI: 10.1016/j.surfcoat.2004.09.032

Abstract anzeigen

A novel magnetic filter with the triangular section has been designed to remove the macro- and nano-particles from the pulsed cathodic arc plasmas utilized to prepare the tetrahedral amorphous carbon (ta-C) films. The macro- and nano-particles at the surfaces of ta-C films were observed using an optical microscope and an atomic force microscope. The filter was found to be very effective in removing the macro- and nano-particles due to its zigzag-type inner surface structure. Particles that collided with the inner surface of the filter were reflected along the direction opposite to the plasma beam, and therefore separated from the arc plasma. The effect of arc current on the filter efficiency has also been investigated.

Zeitschriftenartikel

Peter Breitschopf
Günther Benstetter
B. Knoll
Werner Frammelsberger

Intermittent contact scanning capacitance microscopy-A novel method for 2D doping profiling.

In: Microelectronics Reliability (vol. 45) , pg. 1568-1571

(2005)

Abstract anzeigen

In the present study an improved method for 2D doping profiling of semiconductor device structures is presented. The method combines the capabilities of scanning capacitance microscopy (SCM) with the advantages of intermittent contact atomic force microscopy (IC-AFM) and is called intermittent contact scanning capacitance microscopy (IC-SCM). Compared with standard SCM, IC-SCM provides mechanically stable measurement conditions because tip wear is nearly eliminated. Furthermore, background signals without local information are suppressed by demodulating the SCM signal at higher harmonics of the tapping tip frequency. Both, reduced tip wear and higher harmonics demodulation yield improved spatial image resolution at less tip degradation compared with standard SCM.

Vortrag

Peter Breitschopf
Günther Benstetter
B. Knoll
Werner Frammelsberger

Intermittent contact scanning capacitance microscopy-A novel method for 2D doping profiling.

Arcachon, Frankreich 2005.

(2005)

Zeitschriftenartikel

D. Liu
J. Zhang
Y. Liu
J. Xu
Günther Benstetter

Growth processes and surface properties of diamondlike carbon films.

In: Journal of Applied Physics (vol. 97) , pg. 104901

(2005)

DOI: 10.1063/1.1890446

Abstract anzeigen

In this study, we compare the deposition processes and surface properties of tetrahedral amorphous carbon (ta-C) films from filtered pulsed cathodic arc discharge (PCAD) and hydrogenated amorphous carbon (a-C:H) films from electron cyclotron resonance (ECR)-plasma source ion implantation. The ion energy distributions (IEDs) of filtered-PCAD at various filter inductances and Ar gas pressures were measured using an ion energy analyzer. The IEDs of the carbon species in the absence of background gas and at low gas pressures are well fitted by shifted Maxwellian distributions. Film hardness and surface properties show a clear dependence on the IEDs. ta-C films with surface roughness at an atomic level and thin (0.3–0.9 nm) graphitelike layers at the filmsurfaces were deposited at various filter inductances in the highly ionized plasmas with the full width at half maximum ion energy distributions of 9–16 eV. The a-C:H filmsdeposited at higher H/C ratios of reactive gases were covered with hydrogen and sp3 bonded carbon-enriched layers due to the simultaneous interaction of hydrocarbon species and atomic hydrogen. The effects of deposited species and ion energies on filmsurface properties were analyzed. Some carbon species have insufficient energies to break the delocalized π(nC)bonds at the graphitelike filmsurface, and they can govern filmformation via surface diffusion and coalescence of nuclei. Dangling bonds created by atomic hydrogen lead to uniform chemisorption of hydrocarbon species from the ECR plasmas. The deposition processes of ta-C and a-C:H films are discussed on the basis of the experimental results.

Zeitschriftenartikel

D. Liu
Günther Benstetter

Conducting atomic force microscopy for nanoscale electron emissions from various diamond-like carbon films.

In: Applied Surface Science (vol. 249) , pg. 315-321

(2005)

DOI: 10.1016/j.apsusc.2004.12.029

Abstract anzeigen

Conducting atomic force microscopy (C-AFM) has been used to compare the nanoscale electron emissions from hydrogen-free (a-C), hydrogenated (a-C:H), and tetrahedral (ta-C) diamond-like carbon films. The current measurements are performed on the locations where the low-resistant surface layers are removed. The measurements show the uniform electron emissions from a-C:H and ta-C films. The inhomogeneous electron emission from the a-C film is primarily due to the conducting graphite clusters inside the film. The analysis of Fowler–Nordheim tunnelling currents indicates the formation of filament-like emission channels inside these films. The implications of film structures for electron field emissions are discussed.

Vortrag

Günther Benstetter
D. Liu
Werner Frammelsberger

Advanced Atomic Force Microscopy Techniques for Nano-Scale Analysis.

Wien, Österreich 2005.

(2005)

Vortrag

Günther Benstetter
Peter Breitschopf
B. Knoll
Edgar Lodermeier
Alexander Hofer
Werner Frammelsberger

Intermittent Contact Scanning Capacitance Microscopy-First Results.

Infineon Technologies.

Villach, Österreich 10.11.2005.

(2005)

Vortrag

Günther Benstetter
Werner Frammelsberger
Edgar Lodermeier
Heiko Ranzinger
D. Liu
Peter Breitschopf
W. Bergbauer
Alexander Hofer

Raster-Sonden-Mikroskopie (SPM) in der Fehler- und Zuverlässigkeitsanalytik.

Grainau 2006.

(2006)

Zeitschriftenartikel

Werner Frammelsberger
Günther Benstetter
J. Kiely
R. Stamp

Thickness determination of thin and ultra-thin SiO2 films by C-AFM IV-spectroscopy.

In: Applied Surface Science (vol. 252) , pg. 2375-2388

(2006)

Abstract anzeigen

Conductive atomic force microscopy was used to determine the electrical oxide thickness for five different silicon dioxide layers with thickness in the order of 1.6–5.04 nm. The electrical thickness results were compared with values determined by ellipsometry. A semi-analytical tunnelling current model with one single parameter set was used to superpose current/voltage curves in both the direct tunnelling and the Fowler–Nordheim tunnelling regime regions. The overall electrical oxide thickness was determined by statistical means from results of nearly 3000 IV-curves recorded for different conductive CoCr-coated tips. Good agreement between the shape of model and experimental data was achieved, widely independent of the oxide thickness. Compared with the ellipsometry value, the electrical thickness was larger by a value of 0.36 nm (22%) for the thinnest oxide and smaller by a value of 0.31 nm (6%) for the thickest oxide, while intermediate values yielded differences better than 0.15 nm (<<6%). The physical differences between the measurement techniques were shown to contribute to this observation. In addition, statistical deviations between single and multiple measurements using a single tip and using a number of different tips were analysed. The causes, for example, natural oxide thickness variations, tip wear, air humidity induced effects and contaminations, are evaluated and discussed. The method proposed was able to determine the electrical oxide thickness with a standard deviation in the order of ±±6–9%. The results suggest that for optimal results it is necessary to perform several repetitions of IV-measurements for one sample and, in addition, to employ more than one tip.

Zeitschriftenartikel

D. Liu
S. Zhang
S.-E. Ong
Günther Benstetter
H. Du

Surface and electron emission properties of hydrogen-free diamond-like carbon films investigated by atomic force microscopy.

In: Materials Science & Engineering A (vol. 426) , pg. 114-120

(2006)

Abstract anzeigen

In this study, we have deposited hydrogen-free diamond-like carbon (DLC) films by using DC magnetron sputtering of graphite target at various r.f. bias voltages. Surface and nanoscale emission properties of these DLC films have been investigated using a combination of atomic force microscopy (AFM)-based nanowear tests and conducting-AFM, by simultaneously measuring the topography and the conductivity of the samples. Nanowear tests show that these DLC films are covered with the thin (1.5–2.0 nm) graphite-like layers at surfaces. Compared to the film bulk structure, the graphite-like surface layers are more conductive. The graphite-like surface layers significantly influence the electron emission properties of these films. Low-energy carbon species can be responsible for the formation of graphite-like surface layers. Nanoscale electron emission measurements have revealed the inhomogeneous emission nature of these films. The low-field emission from these films can be attributed to the existence of sp2-configured nanoclusters inside the films.

Zeitschriftenartikel

D. Liu
Y. Liu
J. Li
T. Ma
Günther Benstetter

Properties and deposition processes of a-C: H films from CH4/Ar dielectric barrier discharge plasmas.

In: Surface & Coatings Technology (vol. 200) , pg. 5819-5822

(2006)

Abstract anzeigen

Hydrogenated amorphous carbon (a-C: H) films were deposited from CH4+ Ar gas with low-pressure dielectric barrier discharge (DBD) plasmas. The deposition rate, film hardness and surface roughness were examined as a function of Ar concentration in CH4+ Ar. The experimental results revealed that both film hardness and surface roughness increase with increasing Ar concentration from 20% to 67%, and then decrease for Ar concentration exceeding 67%. Also, the deposition rate decreases monotonously with increasing Ar concentration. The high ratio of Ar+ flux per hydrocarbon species for the cases of Ar concentration exceeding 67% leaded to the decrease in growth rate and in surface roughness. CH4+ and Ar+ kinetic energies during the film deposition process were also analyzed theoretically based on ion drift-diffuse model. The theoretical analysis on ion kinetic energy indicated that the deposition of dense a-C: H film is proportional to an increase in kinetic energy of the hydrocarbon ion and the sputter of energetic Ar+ ions.

Zeitschriftenartikel

D. Liu
Günther Benstetter
Werner Frammelsberger

Nanoscale electron field emissions from the bare, hydrogenated and graphite-like layer covered tetrahedral amorphous carbon films.

In: Journal of Applied Physics (vol. 99) , pg. 044303-044303-8

(2006)

DOI: 10.1063/1.2171806

Abstract anzeigen

We have compared nanoscale electron field emissions from the bare, hydrogenated, and graphitelike-layer-covered tetrahedral amorphous carbon (ta-C) films. The electron field emission is investigated using a combination of atomic force microscopy (AFM)-based nanowear tests and conducting AFM, by simultaneously measuring the topography and the conductivity of the samples. The analysis of Fowler-Nordheim tunneling currents indicates the formation of filamentlike emission channels within ta-C films. The low-field emission from carbon films is primarily due to a field enhancement arising from conducting nanostructures inside the films. The implications of surface structures for electron field emission are discussed. Electrons are easily delocalized within sp2-bonded rings/chains at a film surface, which leads to an increase in the nanotip emission area. At identical emission currents of 60–80 pA, hydrogenated films are much more easily destroyed due to a relatively insulating surface structure. The results suggest that a very high emission site density, required for field-emission display applications, may be produced by locally modifying a film surface layer.

Zeitschriftenartikel

W. Bergbauer
T. Lutz
Werner Frammelsberger
Günther Benstetter

Kelvin Probe Force Microscopy – An appropriate tool for the electrical characterisation of LED heterostructures.

In: Microelectronics Reliability (vol. 46) , pg. 1736-1740

(2006)

Abstract anzeigen

Light Emitting Diodes (LEDs) are commercially important devices in opto-semiconductor industry. The light emitting properties of LEDs degrade with time of operation and may lead to device failure. Even though the stability and reliability of LEDs are important topics, they are not well researched with AFM to date. This work demonstrates that Kelvin Probe Force Microscopy (KPFM) is an appropriate method to identify specific sites of increased degradation in a semiconductor heterostructure. Furthermore, the study shows that KPFM provides the metrological basis for further investigations with respect to the progress of degradation and its physical background. In this study, KPFM has been used to measure the potential gradient over cross-sectioned LED heterostructure in operation at different states of degradation. The results show significant differences between new and aged LEDs, markedly at specific layers of the LED heterostructure.

Vortrag

Günther Benstetter
Peter Breitschopf
B. Knoll
Werner Frammelsberger

Intermittent contact scanning capacitance microscopy – An improved method for 2D doping profiling.

Helsinki, Finnland 16.-18.05.2006.

(2006)

Vortrag

Günther Benstetter
W. Bergbauer
T. Lutz
Werner Frammelsberger

Kelvin Probe Force Microscopy – An appropriate tool for the electrical characterisation of LED heterostructures.

Helsinki, Finnland 16.-18.05.2006.

(2006)

Vortrag

S. Gsell
M. Schreck
Günther Benstetter
et al.

Combined AFM-SEM Study of the Diamond Nucleation Layer on Ir(001).

Estoril, Portugal 03.-08.09.2006.

(2006)

Vortrag

Günther Benstetter
W. Bergbauer
T. Lutz
Werner Frammelsberger

Kelvin Probe Force Microscopy – An appropriate tool for the electrical characterisation of LED heterostructures.

Wuppertal 03.-06.10.2006.

(2006)

Vortrag

Günther Benstetter

Advanced Methods in Scanning Probe Microscopy (SPM).

Dalian Nationalities University.

Dalian, China 2007.

(2007)

Zeitschriftenartikel

Werner Frammelsberger
Günther Benstetter
J. Kiely
R. Stamp

C-AFM-based thickness determination of thin and ultra-thin SiO2 films by use of different conductive-coated probe tips.

In: Applied Surface Science (vol. 253) , pg. 3615-3626

(2007)

Abstract anzeigen

The influence of the probe tip type on the electrical oxide thickness result was researched for four differently coated conductive tip types using SiO2 (oxide) films with optical thickness of 1.7–8.3 nm. For this purpose, conductive atomic force microscopy (C-AFM) was used to measure more than 7200 current–voltage (IV) curves. The electrical oxide thickness was determined on a statistical basis from the IV-curves using a recently published tunnelling model for C-AFM application. The model includes parameters associated with the probe tip types used. The evolution of the tip parameters is described in detail. For the theoretical tip parameters, measured and calculated IV-curves showed excellent agreement and the electrical oxide thickness versus the optical oxide thickness showed congruent behaviour, independent of the tip type. However, differences in the electrical oxide thickness were observed for the different tip types. The theoretical parameters were modified experimentally in order to reduce these differences. Theoretical and experimental tip parameters were compared and their effect on the differences in the electrical oxide thickness is discussed for the different tip types. Overall, it is shown that the proposed model provides a comprehensive framework for determining the electrical oxide thickness using C-AFM, for a wide range of oxide thicknesses and for differently coated conductive tips.

Zeitschriftenartikel

S. Gsell
M. Schreck
Günther Benstetter
Edgar Lodermeier
B. Stritzker

Combined AFM-SEM Study of the Diamond Nucleation Layer on Ir(001).

In: Diamond and Related Materials (vol. 16) , pg. 665-670

(2007)

Abstract anzeigen

During bias enhanced nucleation (BEN) of diamond on iridium the nucleation centres are gathered in discrete islands — the so called “domains”. The topographic signature of these domains has been clarified in the present study by two different concepts. First scanning electron microscopy (SEM) and atomic force microscopy (AFM) were combined to take images with both techniques of a small identical area on a standard BEN sample. In spite of the 2–3 nm deep roughening of the iridium it turned clearly out that the surface shows a 1 nm deep depression within the domains compared with the surface of the surrounding layer. On a second sample which did not show the normal roughening the domains could be identified directly from AFM images. The topographic signature of the domains was the same. Conductive AFM measurements showed that inside and outside the domains the carbon nucleation layer behaves like a high resistivity dielectric sustaining fields up to 107 V/cm. Finally, the temporal development of the domain patterns was studied by consecutive biasing steps on one sample. Depending on the local ion bombardment conditions we observed lateral growth or shrinkage on the same sample. This result suggests that domain formation is a continuous process during the whole BEN procedure starting from a local nucleation event and subsequent lateral expansion.

Zeitschriftenartikel

M. Lanza
M. Porti
M. Nafría
Günther Benstetter
Werner Frammelsberger
Heiko Ranzinger
Edgar Lodermeier
G. Jaschke

Influence of the manufacturing process on the electrical properties of thin (< 4 nm) Hafnium based high-k stacks observed with CAFM.

In: Microelectronics Reliability (vol. 47) , pg. 1424-1428

(2007)

Abstract anzeigen

In this work, the dependence of the electrical characteristics of some thin (<4 nm) HfO2, HfSiO and HfO2/SiO2 stacks on their manufacturing process is studied at the nanoscale. Topography, current maps and current–voltage (I–V) characteristics have been collected by conductive atomic force microscope (CAFM), which show that their conductivity depends on some manufacturing parameters. Increasing the annealing temperature, physical thickness or Hafnium content makes the structure less conductive.

Vortrag

M. Lanza
M. Porti
M. Nafría
Günther Benstetter
Werner Frammelsberger
Heiko Ranzinger
Edgar Lodermeier
G. Jaschke

Influence of the manufacturing process on the electrical properties of thin (< 4 nm) Hafnium based high-k stacks observed with CAFM.

Arcachon, Frankreich 2007.

(2007)

Vortrag

Günther Benstetter

Scanning Probe Microscopy: Analyses for Opto Semiconductors and Outlook.

Osram OS.

Regensburg 2008.

(2008)

Zeitschriftenartikel

R. Biberger
Günther Benstetter
T. Schweinböck
Peter Breitschopf
H. Göbel

Intermittent-contact scanning capacitance microscopy versus contact mode SCM applied to 2D dopant profiling.

In: Microelectronics Reliability (vol. 48 (8-9)) , pg. 1339-1349

(2008)

Abstract anzeigen

This study compares two different methods of scanning capacitance microscopy (SCM). The first and approved one operates in contact mode and the second novel one in intermittent-contact (IC) mode. Measurements were performed on several samples and the results are compared. New technical expertises on the novel intermittent-contact method are shown and in conclusion assets and drawbacks of this SCM method are emphasized.

Vortrag

Günther Benstetter

Raster-Sonden-Mikroskopie an Laser Heterostrukturen.

Regensburg 2008.

(2008)

Vortrag

Günther Benstetter
R. Biberger
D. Liu

A Review of Advanced Scanning Probe Microscope Analysis of Functional Films and Semiconductor Devices. Invited Talk.

Singapur Juli 2008.

(2008)

Zeitschriftenartikel

M. Lanza
M. Porti
M. Nafría
X. Aymerich
Günther Benstetter
Edgar Lodermeier
Heiko Ranzinger
G. Jaschke
S. Teichert
L. Wilde
P. Michalowski

Crystallization and silicon diffusion nanoscale effects on the electrical properties of Al2O3 based devices.

In: Microelectronic Engineering (vol. 86) , pg. 1921-1924

(2009)

Abstract anzeigen

In this work, Atomic Force Microscopy (AFM) based techniques are used to study, at the nanoscale, the dependence of the electrical properties of Al2O3 stacks for Flash memories on the percent of diffused Silicon and material crystallization after being annealed at different temperatures.

Zeitschriftenartikel

Günther Benstetter
R. Biberger
D. Liu

A Review of Advanced Scanning Probe Microscope Analysis of Functional Films and Semiconductor Devices.

In: Thin Solid Films (vol. 517) , pg. 5100-5105

(2009)

Abstract anzeigen

This paper gives an overview of established methods and new developments in the field of Scanning Probe Microscopy (SPM) of functional films and semiconductor devices. It focuses on both, SPM analyses of passive structures and devices in operation. The contribution includes techniques such as Scanning Capacitance Microscopy (SCM) and Scanning Spreading Resistance Microscopy (SSRM) for implant mapping, Conductive AFM (C-AFM) for thin dielectrics analysis and Kelvin Probe Force Microscopy (KPFM) to study the potential distribution across active electronic devices. Finally combinations of different SPM-based techniques are described and future challenges for SPM-based techniques are discussed.

Zeitschriftenartikel

Y. Yin
D. Li
J. Gu
Z. Feng
J. Niu
Günther Benstetter
et al.

Surface properties of silicon oxide films deposited using low pressure dielectric discharge.

In: Applied Surface Science (vol. 255) , pg. 7708-7712

(2009)

Abstract anzeigen

The deposition of SiOX films from low-pressure dielectric barrier discharge plasmas has been investigated using tetraethoxysilane (TEOS)/O2 as the feed gas. Films were analyzed using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), AFM-based nanoindentation/nanowear techniques, and conductive AFM. Film deposition rates and hydrocarbon incorporation in the SiOX film decrease with addition of O2. High-quality SiOX films with extremely low surface roughness are deposited at high oxidant concertrations. Addition of oxidant to the feed gas leads to a change in the SiOX film structure from precursor-like to a dense SiOX structure. The SiOX films deposited with TEOS/O2 plasmas were found to have soft surface layers, 0.5–1.5 nm thick, which contribute to an improvement of their field emission properties. The effect of gas phase compositions on the surface properties of the conductive surface layer was discussed.

Zeitschriftenartikel

R. Biberger
Günther Benstetter
H. Göbel

Displacement current sensor for contact and intermittent contact scanning capacitance microscopy.

In: Microelectronics Reliability (vol. 49) , pg. 1192-1195

(2009)

Abstract anzeigen

In this study a displacement current capacitance sensor (DCCS) for scanning capacitance microscopy (SCM) is introduced. It can be used for both intermittent contact (IC) and contact-SCM operation. Based on I/V conversion and subsequent lock-in amplification a displacement current can be detected and used as a measure for dopant concentration. Therefore a periodic variation of the AFM tip substrate capacitance is required. This can be achieved either by a periodic tip oscillation (IC-SCM) or an applied AC voltage between tip and sample (contact-SCM). The advantage of the DCCS is the linearity, which makes it possible to detect absolute dopant concentrations.

Vortrag

M. Lanza
M. Porti
M. Nafría
X. Aymerich
Günther Benstetter
et al.

Crystallization and Silicon Diffusion Nanoscale Effects on the Electrical Properties of Al2O3 Based Devices.

Cambridge, Großbritannien Juni 2009.

(2009)

Zeitschriftenartikel

D. Liu
J. Gu
Z. Feng
D. Li
J. Niu
Günther Benstetter

Comparison of fluorocarbon film deposition by pulsed/continuous wave and downstream radio frequency plasmas.

In: Vacuum (vol. 85) , pg. 253-262

(2010)

Abstract anzeigen

Fluorocarbon (FC) films have been deposited using pulsed and continuous wave (cw) radio frequency (rf) plasmas fed with hexafluoroethane (C2F6), octafluoropropane (C3F8), or octafluorocyclobutane (C4F8). The effects of feed gases used, discharge pressure, rf power, substrate positions and discharge modes (pulsed or cw) on the deposited films are examined. Film properties are determined using X-ray photoelectron spectroscopy, atomic force microscopy, and static contact angle measurements. The contact angles of FC films are well related to their compositions and structures. Feed gases used, discharge pressure, rf power, substrate positions and discharge modes strongly affect the morphology of the resulting film, as revealed by atomic force microscopy. Optical emission spectrometry measurements were performed to in-situ characterize the gas-phase compositions of the plasmas and radicals’ emission intensities during film deposition. Correlations between film properties, gas-phase plasma diagnostic data, and film growth processes were discussed. The film growth in pulsed or downstream plasmas was controlled by the surface migration of radicals, such as CF2 towards nucleation centers, which result in the deposition of FC films with less cross-linked nature and rougher surfaces. These results demonstrate that it is possible to control film compositions and surface structure by changing deposition parameters.

Zeitschriftenartikel

J. Niu
H.-X. Ding
Y. Cong
N. Yu
Günther Benstetter
D. Liu

Plasma-assisted chemical vapor deposition of titanium oxide films by dielectric barrier discharge. Submitted Article.

In: Thin Solid Films

(2010)

Zeitschriftenartikel

R. Biberger
Günther Benstetter
et al.

Intermittent-Contact Capacitance Spectroscopy – A new method for determining C(V) curves with sub-micron lateral resolution.

In: Microelectronics Reliability (vol. 50) , pg. 1511-1513

(2010)

Abstract anzeigen

This study introduces a novel method to measure C(V) characteristics of local MOS structures based on scanning probe microscopy (SPM) techniques. The new method operates in intermittent-contact (IC) mode and combines both the advantages of contact mode C(V) spectroscopy and intermittent-contact scanning capacitance microscopy. As a consequence, on the one hand dopant concentration and dopant type can be indicated simultaneously, on the other hand tip wear is reduced significantly.

Patentschrift

Günther Benstetter
et al.

Method and apparatus for two-dimensional profiling of doping profiles of a material sample with scanning capacitance microscope.

(2010)

Vortrag

R. Biberger
Günther Benstetter

Displacement Current Sensor for two-dimensional dopant profiling.

Grainau Mai 2010.

(2010)

Vortrag

Günther Benstetter
R. Biberger
Alexander Hofer
H. Göbel

Intermittent-Contact Scanning Capacitance Analysis of Thin Dielectric Films and Semiconductor Devices. Invited Talk.

Harbin, China Juli 2010.

(2010)

Zeitschriftenartikel

A. Bayerl
M. Lanza
M. Porti
F. Campabadal
M. Nafría
X. Aymerich
Günther Benstetter

Reliability and gate conduction variability of HfO2-based MOS devices: A combined nanoscale and device level study.

In: Microelectronic Engineering (vol. 88) , pg. 1334-1337

(2011)

Abstract anzeigen

The electrical properties and reliability of MOS devices based on high-k dielectrics can be affected when the gate stack is subjected to an annealing process, which can lead to the polycrystallization of the high-k layer. In this work, a Conductive Atomic Force Microscope (C-AFM) has been used to study the nanoscale electrical conduction and reliability of amorphous and polycrystalline HfO2 based gate stacks. The link between the nanoscale properties and the reliability and gate conduction variability of fully processed MOS devices has also been investigated.

Zeitschriftenartikel

M. Lanza
M. Porti
M. Nafría
X. Aymerich
Günther Benstetter
Edgar Lodermeier
Heiko Ranzinger
G. Jaschke
S. Teichert
L. Wilde
P. Michalowski

Conductivity and Charge Trapping After Electrical Stress in Amorphous and Polycrystalline Al2O3-Based Devices Studied With AFM-Related Techniques.

In: IEEE Transactions on Nanotechnology (vol. 10) , pg. 344-351

(2011)

Abstract anzeigen

In this paper, atomic force microscopy-based techniques have been used to study, at nanoscale, the dependence of the electrical properties of Al2O3 stacks for flash memories on the annealing temperature (T-A). The electrical characterization has been combined with other techniques (for example, transmission electron microscopy) that have allowed to investigate the dependence of the stack crystallization and the Si diffusion from the substrate to the gate oxide on T-A. The combination of both the analyses has allowed to explore if there is a relation between the percentage of diffused silicon and material crystallization with the conductivity and charge trapping of Al2O3 stacks.

Zeitschriftenartikel

V. Iglesias
M. Lanza
K. Zhang
A. Bayerl
M. Porti
M. Nafría
X. Aymerich
Günther Benstetter
Z. Shen
G. Bersuker

Degradation of polycrystalline HfO2 based gate dielectrics under nanoscale electrical stress.

In: Applied Physics Letters (vol. 99) , pg. 103510

(2011)

Abstract anzeigen

The evolution of the electrical properties of HfO2/SiO2/Si dielectric stacks under electrical stress has been investigated using atomic force microscope-based techniques. The current through the grain boundaries (GBs), which is found to be higher than thorough the grains, is correlated to a higher density of positively charged defects at the GBs. Electrical stress produces different degradation kinetics in the grains and GBs, with a much shorter time to breakdown in the latter, indicating that GBs facilitate dielectric breakdown in high-k gate stacks.

Zeitschriftenartikel

A. Bayerl
M. Lanza
M. Porti
M. Nafría
X. Aymerich
F. Campabadal
Günther Benstetter

Nanoscale and Device Level Gate Conduction Variability of High-k Dielectrics-Based Metal-Oxide-Semiconductor Structures.

In: IEEE Transactions on Device and Materials Reliability (vol. 11) , pg. 495-501

(2011)

DOI: 10.1109/TDMR.2011.2161087

Abstract anzeigen

The polycrystalline microstructure of the high-k dielectric of gate stacks in metal-oxide-semiconductor (MOS) devices can be a potential source of variability. In this paper, a conductive atomic force microscope (CAFM) and a Kelvin probe force microscope (KPFM) have been used to investigate how the thickness and the crystallization (after a thermal annealing) of the high-k layer affect the nanoscale morphological and electrical properties of the gate stack. The impact of such nanoscale properties on the reliability and variability of the global gate electrical characteristics of fully processed MOS devices has also been investigated.

Vortrag

Alexander Hofer
B. Wilke
R. Biberger
Günther Benstetter
H. Göbel

Capacitance and Conductivity Mapping of Organic Films and Devices with Non-Contact SPM Methods.

Max Planck Institute for Polymer Research.

Mainz Juni 2011.

(2011)

Vortrag

Günther Benstetter

Novel Scanning Capacitance Microscopy Techniques for Device and Thin Film Characterization.

Dalian Nationalities University.

Dalian, China 16.11.2011.

(2011)

Vortrag

Günther Benstetter

New Trends in Electrical Scanning Probe Microscopy Techniques for Device and Thin Film Characterization.

Beijing University.

Peking, China 17.11.2011.

(2011)

Vortrag

S. Rogowsky
R. Ostendorf
G. Kaufel
W. Pletschen
J. Wagner
S. Liebich
M. Zimprich
K. Volz
W. Stolz
B. Kunert
Edgar Lodermeier
Heiko Ranzinger
Günther Benstetter

Characteristics of diode laser structures on silicon substrates based on the Ga(NAsP)/(BGa)(AsP) materials combination.

San Francisco, CA, USA Januar 2012.

(2012)

Vortrag

Tobias Berthold
Günther Benstetter
Werner Frammelsberger
R. Rodríguez
M. Nafría
Raimund Förg

Analysis of copper oxide films by combined scanning microscopy.

Singapur, Singapur 14.-17.07.2012.

(2012)

Vortrag

Alexander Hofer
Günther Benstetter
R. Biberger
C. Leirer
G. Brüderl

Analysis of crystal defects on GaN-based semiconductors with advanced scanning probe microscope techniques. Invited Talk.

Singapur, Singapur 14.-17.07.2012.

(2012)

Zeitschriftenartikel

Alexander Hofer
Günther Benstetter
R. Biberger
C. Leirer
G. Brüderl

Analysis of crystal defects on GaN based semiconductors with advanced scanning probe microscope technique.

In: Thin Solid Films (vol. 544) , pg. 139-143

(2013)

Abstract anzeigen

The correlation of surface pits with leakage currents in gallium nitride (GaN) films are studied with scanning probe microscopy (SPM) techniques. The analyses were performed at both single n-GaN films grown on free-standing GaN and completely processed GaN light-emitting diode (LED) structures on sapphire substrates both grown by metal organic chemical vapor phase epitaxy. Topographical SPM images acquired with ultra-sharp probes were superimposed with current maps obtained by conductive atomic force microscopy (CAFM). The applicability of two different modifications of CAFM techniques has been studied. For both sample types, CAFM has revealed a clear correlation between forward-bias leakage current and locations of surface pits. In case of the LED structure, additional local current–voltage characteristics show that enhanced current conduction occurs in both forward and reverse bias on surface pit positions.

Zeitschriftenartikel

Alexander Hofer
R. Biberger
Günther Benstetter
B. Wilke
H. Göbel

Scanning probe microscopy based electrical characterization of thin dielectric and organic semiconductor films.

In: Microelectronics Reliability (vol. 53) , pg. 1430-1433

(2013)

Abstract anzeigen

Scanning probe microscopy (SPM) techniques offer various characterization methods for thin organic films. However, the majority of the electrical SPM measurements is currently performed in contact mode operation and may lead to severe damage at the surface of soft organic materials. This work shows the electrical characterization of organic insulator and semiconductor films by use of two SPM techniques operating with reduced lateral forces between SPM tip and sample. The first one is intermittent-contact scanning-capacitance-microscopy (IC-SCM) which is used for the detection of the local surface capacitance. The second one is torsional resonance tunneling-atomic-force-microscopy (TR-TUNA) which shows the local conductivity respectively relative film thickness of the sample. It is found that the tunneling current distribution across 50 nm thick organic insulating films is very homogeneous and that inhomogeneities in P3HT and Pentacene films can be pinpointed even if no topographical variations are observable.

Beitrag in Sammelwerk/Tagungsband

Günther Benstetter
Werner Frammelsberger

Raster-Sonden-Mikroskopie.

Analyseverfahren für die Halbleiterelektronik.

München: media mind Verlag pg. 10-16

(2013)

Vortrag

Alexander Hofer
R. Biberger
Günther Benstetter
B. Wilke
H. Göbel

Scanning probe microscopy based electrical characterization of thin dielectric and organic semiconductor films.

Arcachon, Frankreich 30.09.-04.10.2013.

(2013)

Vortrag

Manuel Bogner
Günther Benstetter

Determining the thermal conductivity of thin layers with the macroscopic 3ω method.

Technische Hochschule Deggendorf.

Deggendorf 17.-18.10.2013.

(2013)

Vortrag

Günther Benstetter
Alexander Hofer
Tobias Berthold

Selected Atomic Force Microscopy Methods for the Electrical Characterization of Thin Films and Devices. Invited Talk.

Fethiye, Türkei 24.-27.04.2014.

(2014)

Vortrag

Tobias Berthold
Günther Benstetter
Werner Frammelsberger
R. Rodríguez
M. Nafría

Nanoscale copper oxide characterization with Kelvin Probe Force Microscopy. Posterpräsentation.

Chongquing, China 15.-18.07.2014.

(2014)

Vortrag

Manuel Bogner
Günther Benstetter
Alexander Hofer
H. Gruber

The differential 3ω method for measuring the thermal conductivity of AIN and SI3N4 thin films.

Dubrovnik, Kroatien 13.-16.10.2014.

(2014)

Vortrag

Tobias Berthold
Günther Benstetter
Werner Frammelsberger
R. Rodríguez
M. Nafría

Characterization of Self-Assembled Monolayers on Copper by Scanning Probe Microscopy.

Dubrovnik, Kroatien 13.-16.10.2014.

(2014)

Zeitschriftenartikel

L. Hamann
Günther Benstetter
Alexander Hofer
M. Mattheis
M. Haas
R. Zapf-Gottwick

Use of Coated-Metal Particles in Rear Busbar Pastes to Reduce Silver Consumption.

In: IEEE Journal of Photovoltaics (vol. 5) , pg. 534-537

(2015)

DOI: 10.1109/JPHOTOV.2014.2388080

Abstract anzeigen

Reducing the amount of silver is one of the most important ways to reduce the cost of photovoltaic cells. The common way to reduce silver consumption on a cell is the reduction of the metal content in the paste. We present a new paste with silver-coated nickel particles, reducing the silver amount and still keeping the properties of silver related to oxidation and sintering. This paper shows the limits in conductivity due to porosity and oxidation of coated-metal particle pastes in comparison with silver pastes. Simulations and cell tests show that coated-metal particle pastes reduce silver consumption without decreasing the cell efficiency replacing busbar pastes. Coated-metal particle pastes are able to decrease silver consumption for rear-side busbars to c Ag <; 1.4 mg/cm 2 , leading to a conductivity σ BB = 1.110 5 S/cm, without decreasing cell or module efficiency. The conductivity of coated-metal particle pastes is too low using pastes with coated-metal particles as a replacement for the metallization paste for grid fingers but good enough to replace the silver paste for busbars with a cheap alternative.

Zeitschriftenartikel

Tobias Berthold
Günther Benstetter
Werner Frammelsberger
R. Rodríguez
M. Nafría

Nanoscale characterization of copper oxide films by Kelvin Probe Force Microscopy.

In: Thin Solid Films (vol. 584) , pg. 310-315

(2015)

DOI: 10.1016/j.tsf.2015.01.071

Abstract anzeigen

In this work Peakforce Kelvin Probe Force Microscopy (PF-KPFM) at ambient environment is used to characterize both oxidation states of copper (Cu) surfaces, cupric oxide CuO and cuprous oxide Cu2O, with high lateral resolution. Characteristic values of the contact potential difference were obtained for the copper oxide states. By this means, PF-KPFM measurements enabled to distinguish between the different types of Cu oxide with nanometer resolution and to correlate the oxidation states to local topography features. It was even possible to identify single oxide grains on top of the Cu surface. As a result, PF-KPFM is able to address the needs for nanoscale characterization methods in semiconductor manufacturing or other related technologies where the local oxidation behavior of copper is a critical issue.

Zeitschriftenartikel

Tobias Berthold
Günther Benstetter
Werner Frammelsberger
R. Rodríguez
M. Nafría

Nanoscale characterization of CH3-terminated Self-Assembled Monolayer on copper by advanced scanning probe microscopy techniques.

In: Applied Surface Science (vol. 356) , pg. 921-926

(2015)

DOI: 10.1016/j.apsusc.2015.08.182

Abstract anzeigen

In this study, we used Self-Assembled Monolayer (SAM) with CH3 end-group molecules to protect copper surfaces from oxidation and investigated at nanometer scale the integrity and temperature stability of the protective film. The films were characterized by dynamic Chemical Force Microscopy (dCFM), Torsional Resonance Tunneling Atomic Force Microscopy (TR-TUNA) and Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR). We observed that temperature stress degraded local properties of our SAM films significantly, when compared to unstressed films. After temperature stress at 100 °C, tunneling current increased and hydrophobicity decreased substantially. In combination with the ATR-FTIR results we assigned local high current spots and local hydrophobic variations to cuprous oxide (Cu2O). After temperature stress at 150 °C, the measurements indicate a decomposition of the SAM film and a further oxidation of the copper surface. In addition, the results show that dynamic dCFM and TR-TUNA are appropriate tools to characterize SAM films structurally, chemically and electrically. Most important, in contrast to conventional contact mode Atomic Force Microscopy techniques, we did not observe any damage to the SAM film by dCFM and TR-TUNA measurements.

Zeitschriftenartikel

Q. Yang
Y.-W. You
L. Liu
H. Fan
W. Ni
D. Liu
C. Liu
Günther Benstetter
Y. Wang

Nanostructured fuzz growth on tungsten under low-energy and high-flux He irradiation.

In: Scientific Reports (Nature Publishing Group) (vol. 5) , pg. 1-9

(2015)

DOI: 10.1038/srep10959

Zeitschriftenartikel

Manuel Bogner
Alexander Hofer
Günther Benstetter
H. Gruber
R.Y.Q. Fu

Differential 3ω method for measuring thermal conductivity of AIN and SI3N4 thin films.

In: Thin Solid Films (vol. 591 Part B) , pg. 267-270

(2015)

DOI: 10.1016/j.tsf.2015.03.031

Abstract anzeigen

The thermal conductivity λ of plasma enhanced chemical vapor deposited Si3N4 and sputtered AlN thin films deposited on silicon substrates were obtained utilizing the differential 3ω method. A thin electrically conductive strip was deposited onto the investigated thin film of interest, and used as both a heater and a temperature sensor. To study the thickness dependent thermal conductivity of AlN and Si3N4 films their thickness was varied from 300 to 1000 nm. Measurements were performed at room temperature at a chamber pressure of 3.1 Pa. The measured thermal conductivity values of AlN and Si3N4 thin films were between 5.4 and 17.6 Wm− 1 K− 1 and 0.8 up to 1.7 Wm− 1 K− 1, respectively. The data were significantly smaller than that of the bulk materials found in literature (i.e., λAlN = 250–285 Wm− 1 K− 1, λSi3N4 = 30 Wm− 1 K− 1), due to the scaling effects, and also strongly dependent on film thickness, but were comparable with literature for the corresponding thin films.

Zeitschriftenartikel

Q. Yang
H. Fan
W. Ni
L. Liu
Tobias Berthold
Günther Benstetter
D. Liu
Y. Wang

Observation of interstitial loops in He+ irradiated W by conductive atomic force microscopy.

In: Acta Materialia (vol. 92) , pg. 178-188

(2015)

Zeitschriftenartikel

W. Ni
Q. Yang
H. Fan
L. Liu
Tobias Berthold
Günther Benstetter
D. Liu

Ordered arrangement of irradiation-induced defects of polycrystalline tungsten irradiated with low-energy hydrogen ions.

In: Journal of Nuclear Materials (vol. 464) , pg. 216-220

(2015)

Vortrag

Günther Benstetter
Alexander Hofer
A. Greppmair
M. Brandt

A review of physical characterization methods for nanostructured thermoelectric materials. Invited Talk.

Oludeniz, Türkei 19.-23.10.2015.

(2015)

Vortrag

K. Schiebl
Alexander Hofer
Günther Benstetter

Atomic Force Microscopy analysis of laser-sintered Germanium nanoparticles for thermoelectric applications.

Oludeniz, Türkei 19.-23.10.2015.

(2015)

Zeitschriftenartikel

L. Liu
D. Liu
Y. Hong
H. Fan
W. Ni
Q. Yang
Z. Bi
Günther Benstetter
S. Li

High-flux He+ irradiation effects on surface damages of tungsten under ITER relevant conditions.

In: Journal of Nuclear Materials (vol. 471) , pg. 1-7

(2016)

DOI: 10.1016/j.jnucmat.2016.01.001

Abstract anzeigen

A large-power inductively coupled plasma source was designed to perform the continuous helium ions (He+) irradiations of polycrystalline tungsten (W) under International Thermonuclear Experimental Reactor (ITER) relevant conditions. He+ irradiations were performed at He+ fluxes of 2.3 × 1021–1.6 × 1022/m2 s and He+ energies of 12–220 eV. Surface damages and microstructures of irradiated W were observed by scanning electron microscopy. This study showed the growth of nano-fuzzes with their lengths of 1.3–2.0 μm at He+ energies of >70 eV or He+ fluxes of >1.3 × 1022/m2 s. Nanometer-sized defects or columnar microstructures were formed in W surface layer due to low-energy He+ irradiations at an elevated temperature (>1300 K). The diffusion and coalescence of He atoms in W surface layers led to the growth and structures of nano-fuzzes. This study indicated that a reduction of He+ energy below 12–30 eV may greatly decrease the surface damage of tungsten diverter in the fusion reactor.

Zeitschriftenartikel

H. Fan
Y. You
W. Ni
Q. Yang
L. Liu
Günther Benstetter
D. Liu
C. Liu

Surface degeneration of W crystal irradiated with low-energy hydrogen ions.

In: Scientific Reports (Nature Publishing Group) (vol. 6)

(2016)

DOI: 10.1038/srep23738

Abstract anzeigen

The damage layer of a W (100) crystal irradiated with 120 eV hydrogen ions at a fluence of up to 1.5 × 1025/m2 was investigated by scanning electron microscopy and conductive atomic force microscopy (CAFM). The periodic surface degeneration of the W crystal at a surface temperature of 373 K was formed at increasing hydrogen fluence. Observations by CCD camera and CAFM indicate the existence of ultrathin surface layers due to low-energy H irradiation. The W surface layer can contain a high density of nanometer-sized defects, resulting in the thermal instability of W atoms in the surface layer. Our findings suggest that the periodic surface degeneration of the W crystal can be ascribed to the lateral erosion of W surface layers falling off during the low-energy hydrogen irradiation. Our density functional theory calculations confirm the thermal instability of W atoms in the top layer, especially if H atoms are adsorbed on the surface.

Zeitschriftenartikel

X. Jing
Emanuel Panholzer
X. Song
E. Grustan-Gutierrez
F. Hui
Y. Shi
Günther Benstetter
Y. Illarionov
T. Grasser
M. Lanza

Fabrication of scalable and ultra low power photodetectors with high light/dark current ratios using polycrystalline monolayer MoS2 sheets.

In: Nano Energy (vol. 30) , pg. 494-502

(2016)

DOI: 10.1016/j.nanoen.2016.10.032

Zeitschriftenartikel

Y. Ji
H. Fei
Y. Shi
V. Iglesias
D. Lewis
N. Jiebin
S. Long
M. Liu
Alexander Hofer
Werner Frammelsberger
Günther Benstetter
A. Scheuermann
P. McIntyre
M. Lanza

Characterization of the photocurrents generated by the laser of atomic force microscopes.

In: Review of Scientific Instruments (vol. 87) , pg. 083703

(2016)

DOI: 10.1063/1.4960597

Abstract anzeigen

The conductive atomic force microscope (CAFM) has become an essential tool for the nanoscale electronic characterization of many materials and devices. When studying photoactive samples, the laser used by the CAFM to detect the deflection of the cantilever can generate photocurrents that perturb the current signals collected, leading to unreliable characterization. In metal-coated semiconductor samples, this problem is further aggravated, and large currents above the nanometer range can be observed even without the application of any bias. Here we present the first characterization of the photocurrents introduced by the laser of the CAFM, and we quantify the amount of light arriving to the surface of the sample. The mechanisms for current collection when placing the CAFM tip on metal-coated photoactive samples are also analyzed in-depth. Finally, we successfully avoided the laser-induced perturbations using a two pass technique: the first scan collects the topography (laser ON) and the second collects the current (laser OFF). We also demonstrate that CAFMs without a laser (using a tuning fork for detecting the deflection of the tip) do not have this problem.

Vortrag

Alexander Hofer
Tobias Berthold
A. Greppmair
Günther Benstetter
M. Brandt

Nanoscale characterization of laser-sintered Ge nanoparticle layers.

Graz, Österreich 27.-29.06.2016.

(2016)

Vortrag

Alexander Hofer
Tobias Berthold
A. Greppmair
M. Brandt
Günther Benstetter

Nanoscale electrical conductivity of laser-sintered Ge nanoparticle layers.

Singapur, Singapur 12.-15.07.2016.

(2016)

Beitrag in Sammelwerk/Tagungsband

Günther Benstetter
Alexander Hofer
D. Liu
Werner Frammelsberger
M. Lanza

Chapter 3: Fundamentals of CAFM Operation Modes.

In:
M. Lanza

Weinheim: Wiley-VCH pg. 45-78

(2017)

Beitrag in Sammelwerk/Tagungsband

Tobias Berthold
Günther Benstetter
Werner Frammelsberger
Manuel Bogner
R. Rodríguez
M. Nafría

Protective nanometer films for reliable Cu-Cu connections.

Best Paper Award.

(2017)

Zeitschriftenartikel

Tobias Berthold
Günther Benstetter
Werner Frammelsberger
Manuel Bogner
R. Rodríguez
M. Nafría

Protective nanometer films for reliable Cu-Cu connections.

In: Microelectronics Reliability (vol. 76-77) , pg. 383-389

(2017)

DOI: 10.1016/j.microrel.2017.07.001

Zeitschriftenartikel

C. Yang
D. Souchay
M. Kneiß
Manuel Bogner
H. Wei
M. Lorenz
O. Oeckler
Günther Benstetter
Y. Fu
M. Grundmann

Transparent flexible thermoelectric material based on non-toxic earth-abundant p-type copper iodide thin film.

In: Nature Communications , pg. 1-7

(2017)

DOI: 10.1038/ncomms16076

Abstract anzeigen

Thermoelectric devices that are flexible and optically transparent hold unique promise for future electronics. However, development of invisible thermoelectric elements is hindered by the lack of p-type transparent thermoelectric materials. Here we present the superior room-temperature thermoelectric performance of p-type transparent copper iodide (CuI) thin films. Large Seebeck coefficients and power factors of the obtained CuI thin films are analysed based on a single-band model. The low-thermal conductivity of the CuI films is attributed to a combined effect of the heavy element iodine and strong phonon scattering. Accordingly, we achieve a large thermoelectric figure of merit of ZT=0.21 at 300 K for the CuI films, which is three orders of magnitude higher compared with state-of-the-art p-type transparent materials. A transparent and flexible CuI-based thermoelectric element is demonstrated. Our findings open a path for multifunctional technologies combing transparent electronics, flexible electronics and thermoelectricity.

Zeitschriftenartikel

Tobias Berthold
Günther Benstetter
Werner Frammelsberger
R. Rodríguez
M. Nafría

Numerical Study of Hydrodynamic Forces for AFM Operations in Liquid Scanning (Article ID 6286595, 12 pages).

In: Scanning , pg. 1-12

(2017)

DOI: 10.1155/2017/6286595

Abstract anzeigen

For advanced atomic force microscopy (AFM) investigation of chemical surface modifications or very soft organic sample surfaces, the AFM probe tip needs to be operated in a liquid environment because any attractive or repulsive forces influenced by the measurement environment could obscure molecular forces. Due to fluid properties, the mechanical behavior of the AFM cantilever is influenced by the hydrodynamic drag force due to viscous friction with the liquid. This study provides a numerical model based on computational fluid dynamics (CFD) and investigates the hydrodynamic drag forces for different cantilever geometries and varying fluid conditions for Peakforce Tapping (PFT) in liquids. The developed model was verified by comparing the predicted values with published results of other researchers and the findings confirmed that drag force dependence on tip speed is essentially linear in nature. We observed that triangular cantilever geometry provides significant lower drag forces than rectangular geometry and that short cantilever offers reduced flow resistance. The influence of different liquids such as ultrapure water or an ethanol-water mixture as well as a temperature induced variation of the drag force could be demonstrated. The acting forces are lowest in ultrapure water, whereas with increasing ethanol concentrations the drag forces increase.

Vortrag

Manuel Bogner
C. Yang
Günther Benstetter
Y. Fu
M. Grundmann

Nanoscale thermal properties of next generation transparent/flexible thermoelectric copper iodide films. Posterpräsentation.

Hawaii, USA 06.-10.12.2017.

(2017)

Zeitschriftenartikel

L. Liu
S. Li
D. Liu
Günther Benstetter
Y. Zhang
Y. Hong
H. Fan
W. Ni
Q. Yang
Y. Wu
Z. Bi

Surface damages of polycrystalline W and La2O3-doped W induced by high-flux He plasma irradiation.

In: Journal of Nuclear Materials (vol. 501) , pg. 275-281

(2018)

Abstract anzeigen

In this study, polycrystalline tungsten (W) and three oxide dispersed strengthened W with 0.1 vol %, 1.0 vol % and 5.0 vol % lanthanum trioxide (La2O3) were irradiated with low-energy (200 eV) and high-flux (5.8 × 1021 or 1.4 × 1022 ions/m2⋅s) He+ ions at elevated temperature. After He+ irradiation at a fluence of 3.0 × 1025/m2, their surface damages were observed by scanning electron microscopy, energy dispersive spectroscopy, scanning electron microscopy-electron backscatter diffraction, and conductive atomic force microscopy. Micron-sized holes were formed on the surface of W alloys after He+ irradiation at 1100 K. Analysis shows that the La2O3 grains doped in W were sputtered preferentially by the high-flux He+ ions when compared with the W grains. For irradiation at 1550 K, W nano-fuzz was formed at the surfaces of both polycrystalline W and La2O3-doped W. The thickness of the fuzz layers formed at the surface of La2O3-doped W is 40% lower than the one of polycrystalline W. The presence of La2O3 could suppress the diffusion and coalescence of He atoms inside W, which plays an important role in the growth of nanostructures fuzz.

Zeitschriftenartikel

S. Chen
L. Jiang
M. Buckwell
X. Jing
Y. Ji
E. Grustan-Gutierrez
Günther Benstetter
F. Hui
Y. Shi
M. Rommel
A. Paskaleva
W. Ng
A. Mehonic
A. Kenyon
M. Lanza

On the Limits of Scalpel AFM for the 3D Electrical Characterization of Nanomaterials.

In: Advanced Functional Materials (vol. 28) , pg. 1802266

(2018)

DOI: 10.1002/adfm.201802266

Abstract anzeigen

Conductive atomic force microscopy (CAFM) has been widely used for electrical characterization of thin dielectrics by applying a gentle contact force that ensures a good electrical contact without inducing additional high‐pressure related phenomena (e.g., flexoelectricity, local heat, scratching). Recently, the CAFM has been used to obtain 3D electrical images of thin dielectrics by etching their surface. However, the effect of the high contact forces/pressures applied during the etching on the electrical properties of the materials has never been considered. By collecting cross‐sectional transmission electron microscopy images at the etched regions, it is shown here that the etching process can modify the morphology of Al2O3 thin films (producing phase change, generation of defects, and metal penetration). It is also observed that this technique severely modifies the electrical properties of pSi and TiO2 wafers during the etching, and several behaviors ignored in previous studies, including i) observation of high currents in the absence of bias, ii) instabilities of etching rate, and iii) degradation of CAFM tips, are reported. Overall, this work should contribute to understand better the limitations of this technique and disseminate it among those applications in which it can be really useful.

Vortrag

Manuel Bogner
C. Yang
Günther Benstetter
Y. Fu
M. Grundmann

Nanoscale thermal properties of next generation transparent/flexible thermoelectric copper iodide films. Posterpräsentation.

Technische Hochschule Deggendorf.

Deggendorf 08.03.2018.

(2018)

Vortrag

Tobias Berthold
Günther Benstetter
Werner Frammelsberger
Manuel Bogner
R. Rodríguez
M. Nafría

Protective nanometer films for reliable Cu-Cu connections. Invited Talk.

San Francisco, CA, USA 11.-15.03.2018.

(2018)

Vortrag

D. Liu
H. Fan
L. Liu
Y. You
Günther Benstetter
F. Zhang

Surface diffusion and growth of W self-interstitials during low-energy and large-flux H/He ion irridiations of polycrystalline W.

Princeton University, NJ, USA 17.-22.06.2018.

(2018)

Vortrag

Günther Benstetter
Christoph Metzke
W. Lehermeier

Advances in Electrical and Thermal Characterization of Surfaces and Thin Films. Invited Talk.

Venedig, Italien 23.-25.10.2018.

(2018)

Vortrag

Christoph Metzke
W. Lehermeier
Günther Benstetter
Werner Frammelsberger

Evaluation of Topography effects of SThM Measurements on Thin Thermoelectric Films. Poster.

Venedig, Italien 23.-25.10.2018.

(2018)

Zeitschriftenartikel

Z. Bi
D. Liu
Y. Zhang
L. Liu
Y. Xia
Y. Hong
H. Fan
Günther Benstetter
G. Lei
L. Yan

The evolution of He nanobubbles in tungsten under fusion-relevant He ion irradiation conditions.

In: Nuclear Fusion (vol. 59) , pg. 086025

(2019)

DOI: 10.1088/1741-4326/ab2472

Abstract anzeigen

He-induced W nanofuzz growth over the W divertor target is one of the main limiting factors affecting the current design and development of fusion reactors. In this paper, based on He reaction rate model in W, we simulate the growth and evolution of He nanobubbles during W nanofuzz formation under fusion-relevant He+ irradiation conditions. Our modeling unveils the existence of He nanobubble-enriched W surface layer (<10 nm), formed due to the He diffusion in W crystal into defect sites. At an elevated temperature, the growth of He bubbles in the W surface layer prevents He atoms diffusing into the deep layer (>10 nm). The formation of W nanofuzz at the surface is attributed to surface bursting of high-density He bubbles with their radius of ~4 nm, and an increase in the surface area of irradiated W. Our findings have been well confirmed by the experimental measurements.

Zeitschriftenartikel

W. Ni
L. Liu
Y. Zhang
H. Fan
G. Song
D. Liu
Günther Benstetter
G. Lei

Mass loss of pure W, W-Re alloys, and oxide dispersed W under ITER-relevant He ion irradiations.

In: Journal of Nuclear Materials (vol. 527) , pg. 151800

(2019)

DOI: 10.1016/j.jnucmat.2019.151800

Abstract anzeigen

In this study, polycrystalline W, W-Re alloys, and La2O3 and Y2O3 dispersion-strengthened W have been irradiated by our large-power materials irradiation experimental system (LP-MIES) at the irradiation temperature of 1360–1460 K. Our measurements show that the W nano-fuzz layer which is < 5.2 μm thick has been formed over all the specimens exposed to the low-energy (50 or 100 eV) and high-flux (1.37 × 1022–1.62 × 1022 ions/m2⋅s) He+ irradiations. The mass loss of the fuzz layer almost linearly increases with the He+ fluence, which does not show any dependence on the thickness of fuzz layer varying from 1.1 to 5.2 μm La2O3 and Y2O3 dispersions into W significantly suppress the growth of W fuzz, indicating that He diffusion and the evolution of He nano-bubbles in the near-surface can be significantly influenced due to the dispersion. After He+ (100 eV) irradiation at He+ fluence of 5.83 × 1026/m2, the mass loss of 0.1 vol% - 1.0 vol% La2O3-dispersed W is about 20% lower than the one of the pure W, and the La2O3 dispersed W exhibits the best erosion resistance among various W material grades. Our analysis indicates that both the surface sputtering of W fuzz by energetic ions and surface bursting of He nano-bubbles can be responsible for the mass loss of W under ITER-relevant He+ irradiations.

Beitrag in Sammelwerk/Tagungsband

Christoph Metzke
Günther Benstetter

Thermische Charakterisierung ultradünner Schichten.

In:
Technische Hochschule Deggendorf

Deggendorf pg. 138-141

(2019)

Zeitschriftenartikel

C. Wen
X. Jing
F. Hitzel
C. Pan
Günther Benstetter
M. Lanza

In Situ Observation of Current Generation in ZnO Nanowire Based Nanogenerators Using a CAFM Integrated into an SEM.

In: ACS Applied Materials & Interfaces (vol. 11) , pg. 15183-15188

(2019)

DOI: 10.1021/acsami.9b00447

Abstract anzeigen

In this work, we monitor in situ the movement of ZnO piezoelectric nanowires by using a conductive atomic force microscope integrated into a scanning electron microscope. This setup allows seeing the bending of the nanowires and simultaneously measuring the currents generated. We conclude that the currents generated not only come from piezoelectric effect, but also from contact potential and triboelectric effect. These contributions have been ignored in all previous reports in this field, meaning that the power conversion efficiency of these devices may have been systematically overestimated. Our study helps to clarify the working mechanism of piezoelectric nanogenerators based on ZnO nanowires.

Zeitschriftenartikel

L. Jiang
Jonas Weber
F. Puglisi
P. Pavan
L. Larcher
Werner Frammelsberger
Günther Benstetter
M. Lanza

Understanding Current Instabilities in Conductive Atomic Force Microscopy.

In: Materials (vol. 12) , pg. E459

(2019)

DOI: 10.3390/ma12030459

Abstract anzeigen

Conductive atomic force microscopy (CAFM) is one of the most powerful techniques in studying the electrical properties of various materials at the nanoscale. However, understanding current fluctuations within one study (due to degradation of the probe tips) and from one study to another (due to the use of probe tips with different characteristics), are still two major problems that may drive CAFM researchers to extract wrong conclusions. In this manuscript, these two issues are statistically analyzed by collecting experimental CAFM data and processing them using two different computational models. Our study indicates that: (i) before their complete degradation, CAFM tips show a stable state with degraded conductance, which is difficult to detect and it requires CAFM tip conductivity characterization before and after the CAFM experiments; and (ii) CAFM tips with low spring constants may unavoidably lead to the presence of a ~1.2 nm thick water film at the tip/sample junction, even if the maximum contact force allowed by the setup is applied. These two phenomena can easily drive CAFM users to overestimate the properties of the samples under test (e.g., oxide thickness). Our study can help researchers to better understand the current shifts that were observed during their CAFM experiments, as well as which probe tip to use and how it degrades. Ultimately, this work may contribute to enhancing the reliability of CAFM investigations.

Zeitschriftenartikel

L. Liu
S. Li
D. Liu
Günther Benstetter
O. Man
J. Michalicka
Y. Zhang
Y. Hong
H. Fan
W. Ni
Q. Yang
Y. Wu
Z. Bi

The effect of O2 impurity on surface morphology of polycrystalline W during low-energy and high-flux He+ irradiation.

In: Fusion Engineering and Design (vol. 139) , pg. 96-103

(2019)

DOI: 10.1016/j.fusengdes.2019.01.003

Abstract anzeigen

The interaction between the impurities (such as carbon, nitrogen, oxygen) and the plasma-facing materials (PFMs) can profoundly influence the performance and service of the PFMs. In this paper, we investigated the influence of oxygen (O2) impurity in the helium radio frequency (RF) plasma on the surface morphology of polycrystalline tungsten (W) irradiated at the surface temperature of 1450 ± 50 K and the ion energy of 100 eV. The pressure ratio of O2 to He (R) in RF source varied from 4.0 × 10−6 to 9.0 × 10-2. The total irradiation flux and fluence were ˜1.2 × 1022 ions·m-2·s-1 and ˜1.0 × 1026 ions·m-2, respectively. After He+ irradiation, the specimen surface morphology was observed by scanning electron microscopy. It was found that with increasing R from 4.0 × 10−6 to 9.0 × 10-2 the thickness of nano-fuzz layer at the W surface was thinner and thinner, accompanied by the formation of rod-like structures. The erosion yield increased from 5.2 × 10-4 to 2.3 × 10-2 W/ion when R varied from 4.0 × 10-6 to 9.0 × 10-2. The X-ray diffraction analysis shows that tungsten oxides were formed at the near surface of specimens when R exceeded 1.8 × 10-2. The erosion yield measurements revealed that in addition to surface physical sputtering process, the chemical erosion process could occur due to the interaction between oxygen-containing species and W at the surface. The results indicated that the presence of O2 impurity in He plasma can obviously affect the surface microstructure of W. The study suggested that O2 impurity can effectively reduce the growth of nano-fuzz structures.

Vortrag

Christoph Metzke
Günther Benstetter
Werner Frammelsberger
Jonas Weber
Fabian Kühnel

Temperature dependent investigation of hexagonal boron nitride films using scanning thermal microscopy. Poster presentation.

NanoBio Lab.

Lisbon, Portugal 16.-20.06.2019.

(2019)

Zeitschriftenartikel

W. Ni
Y. Zhang
Y. Cui
C. Niu
L. Liu
H. Fan
Günther Benstetter
G. Lei
D. Liu

The effect of fusion-relevant He ion flux on the evolution of He nano-bubbles in W.

In: Plasma Physics and Controlled Fusion (vol. 62) , pg. 065002

(2020)

DOI: 10.1088/1361-6587/ab8242

Abstract anzeigen

Based on a He reaction rate model in W, we have analyzed the effect of fusion-relevant He+ flux on the evolution and surface bursting of He nano-bubbles in W. The concentrations of solute He atoms, trapped He atoms, and He nano-bubbles, and the radius of He nano-bubbles have been obtained as a function of depth, He+ dose, and He+ flux. He retentions in W are also calculated as the function of He+ dose and flux. Our modeling shows that the He+ flux varying from 5.0 × 1018 to 5.0 × 1024 m−2centerdots−1 significantly affects the concentration of solute He atoms diffusing in W and trapped He atoms, the evolution of He nano-bubbles, and He retention in W. Both the concentration and radius of He nano-bubbles in W show the dependence on He+ flux, and their surface bursting leads to an increase ($\Delta {A_{b - Burst}}$) in the W surface area, thus the growth of W nano-fuzz. When He+ flux increases 5.0 × 1018 to 5.0 × 1024m−2centerdots−1, the bursting rate of He nano-bubbles is greatly reduced, accompanied by an increase in $\Delta {A_{b - Burst}}$. However, $\Delta {A_{b - Burst}}$ is less dependent on the fusion-relevant He+ flux varying from 9.0 × 1020 to 1.6 × 1022m−2centerdots−1, which is consistent with the measured W nano-fuzz growth by He/D2 plasmas.

Zeitschriftenartikel

W. Ni
L. Liu
Y. Zhang
C. Niu
H. Fan
G. Song
D. Liu
Günther Benstetter
G. Lei

Effect of intermittent He/D ion irradiations on W nano-fuzz growth over W targets.

In: Vacuum (vol. 173) , pg. 109146

(2020)

DOI: 10.1016/j.vacuum.2019.109146

Abstract anzeigen

The intermittent He/D ion irradiations of polycrystalline W have been performed at the ion energy of 50 eV by changing the time of the single irradiations and the irradiation temperature. All irradiated W specimens have been observed by scanning electron microscopy, and the effect of intermittent He/D ion irradiations on the W fuzz growth has been analyzed. The W fuzz growth over W targets does not show the clear dependence on the intermittent He/D ion irradiations, where the He/D ion fluence of the single irradiations typically varies from 5.0 × 1024 to 2.5 × 1025/m2. However, a slight change in the W surface temperature during the single He ion irradiations significantly affects the W fuzz growth rate. Analysis indicates that W fuzz growth is significantly affected by the total He ion fluence varying from 5.0 × 1024 to 5.0 × 1025/m2 and the irradiation temperature varying from 1100 to 1450 K. This current study will play a crucial role in understanding the W fuzz growth under the periodic He/D ion irradiations of W divertor in fusion reactors, such as ELMs.

Zeitschriftenartikel

Christoph Metzke
Werner Frammelsberger
Jonas Weber
Fabian Kühnel
K. Zhu
M. Lanza
Günther Benstetter

On the Limits of Scanning Thermal Microscopy of Ultrathin Films.

In: Materials (vol. 13) , pg. 518

(2020)

DOI: 10.3390/ma13030518

Abstract anzeigen

Heat transfer processes in micro- and nanoscale devices have become more and more important during the last decades. Scanning thermal microscopy (SThM) is an atomic force microscopy (AFM) based method for analyzing local thermal conductivities of layers with thicknesses in the range of several nm to µm. In this work, we investigate ultrathin films of hexagonal boron nitride (h-BN), copper iodide in zincblende structure (γ-CuI) and some test sample structures fabricated of silicon (Si) and silicon dioxide (SiO2) using SThM. Specifically, we analyze and discuss the influence of the sample topography, the touching angle between probe tip and sample, and the probe tip temperature on the acquired results. In essence, our findings indicate that SThM measurements include artefacts that are not associated with the thermal properties of the film under investigation. We discuss possible ways of influence, as well as the magnitudes involved. Furthermore, we suggest necessary measuring conditions that make qualitative SThM measurements of ultrathin films of h-BN with thicknesses at or below 23 nm possible.

Zeitschriftenartikel

H. Fan
Y. Zhang
D. Liu
C. Niu
L. Liu
W. Ni
Y. Xia
Z. Bi
Günther Benstetter
G. Lei

Tensile stress-driven cracking of W fuzz over W crystal under fusion-relevant He ion irradiations.

In: Nuclear Fusion (vol. 60) , pg. 046011

(2020)

DOI: 10.1088/1741-4326/ab71bb

Abstract anzeigen

Although W fuzz is formed in the divertor region of the fusion reactor, no theory may clearly explain the W fuzz growth mechanism. In this study, we observe the growth process of W fuzz over W crystal under ITER-relevant He ion irradiations. We propose the tensile stress-driven cracking of nano-structured fuzz during the initial growth of W fuzz. We demonstrate that the existence of tensile stress is due to the swelling of He nano-bubbles in the fuzz. After this cracking, the W fuzz breaks away from the planar network and grows over the W surface, where the micro-stress in the W surface layer acts as the driving force.

Vortrag

Fabian Kühnel
Christoph Metzke
Günther Benstetter

Thermal conductivity measurements of thin films using 3ω method.

Deggendorf 23.07.2020.

(2020)

Vortrag

Christoph Metzke
Fabian Kühnel
Günther Benstetter

Thermal characterization of thin films using FEM simulations.

Deggendorf 23.07.2020.

(2020)

Vortrag

Günther Benstetter
Christoph Metzke
Jonas Weber

Recent Trends in Characterization of Nanoelectronic Materials and Devices with Scanning Probe Microscopy. Invited Talk.

Virtual Conference 10.12.2020.

(2020)

Zeitschriftenartikel

H. Fan
C. Niu
X. Li
W. Liu
Y. Zhang
W. Ni
L. Liu
D. Liu
Günther Benstetter
G. Lei
J. Niu

W fuzz layers: very high resistance to sputtering under fusion-relevant He + irradiations.

In: Plasma Science & Technology (vol. 24) , pg. 015601

(2021)

DOI: 10.1088/2058-6272/ac35a2

Abstract anzeigen

In this study, we have modeled the sputtering process of energetic He+ ions colliding with W nano-fuzz materials, based on the physical processes, such as the collision and diffusion of energetic particles, sputtering and redeposition. Our modeling shows that the fuzzy nanomaterials with a large surface-to-volume ratio exhibit very high resistance to sputtering under fusion-relevant He+ irradiations, and their sputtering yields are mainly determined by the thickness of fuzzy nano-materials, the reflection coefficients and mean free paths of energetic particles, surface sputtering yields of a flat base material, and the geometry of nano-fuzz. Our measurements have confirmed that the surface sputtering yield of a W nano-fuzz layer with the columnar geometry of nano-fuzz in cross-section is about one magnitude of order lower than the one of smooth W substrates. This work provides a complete model for energetic particles colliding with the nano-fuzz layer and clarifies the fundamental sputtering process occurring in the nano-fuzz layer.

Zeitschriftenartikel

Fabian Kühnel
Jonas Weber
Christoph Metzke
Günther Benstetter

Thermoreflectance Imaging neu gedacht. Eine günstige Alternative zur Ermittlung der thermischen Leitfähigkeit.

In: WILEY GIT Labor-Fachzeitschrift

(2021)

Abstract anzeigen

Die thermische Leitfähigkeit dünner Schichten spielt eine zentrale Rolle bei der Entwicklung neuer mikroelektronischer Bauteile. Kann die entstehende Wärme in solchen Bauteilen nicht richtig abgeführt werden, bilden sich Hotspots, welche zu Bauteilversagen führen können. Das Ermitteln der thermischen Leitfähigkeiten, insbesondere bei dünnen Schichten, ist allerdings mit einigem Aufwand und Kosten verbunden. Im Bereich der Prozessoren- und Grafikkartenentwicklung liefern sich die Hersteller ein erbittertes Rennen, um das leistungsstärkste Produkt auf den Markt zu bringen. Dazu werden immer kleinere Transistoren benötigt. Inzwischen ist der dafür benötigte Fertigungsprozess bei einer Größe von 2 nm [1] angelangt. Mit zunehmender Verkleinerung steigt die Leistungsdichte und somit auch die erzeugte Wärme. Kann diese nicht effektiv abfließen, versagt das Bauteil. Dies ist ein entscheidender Grund dafür, weshalb die Untersuchung der thermischen Leitfähigkeit von dünnen Schichten immer mehr an Bedeutung gewinnt. Zur Untersuchung der thermischen Leitfähigkeit gibt es eine Vielzahl an Messmethoden, wie zum Beispiel die Laser-Flash-Methode, die Micro-Raman Methode, die Scanning Thermal Microscopy, die 3-Omega Methode oder die Thermoreflectance Imaging Methode. So unterschiedlich alle diese Methoden auch sind, eines haben sie doch gemeinsam: Sie sind äußerst komplex und benötigen sehr teures Equipment.

Zeitschriftenartikel

C. Niu
Y. Zhang
Y. Cui
X. Li
W. Liu
W. Ni
H. Fan
N. Lu
Günther Benstetter
G. Lei
D. Liu

Effect of temperature on the growth and surface bursting of He nano-bubbles in W under fusion-relevant He ion irradiations.

In: Fusion Engineering and Design (vol. 163) , pg. 112159

(2021)

DOI: 10.1016/j.fusengdes.2020.112159

Abstract anzeigen

Under fusion-relevant He+ irradiations, the W surface temperature is one of the most important parameters for controlling the fuzz growth over the W divertor targets, which is associated with the surface bursting of He nano-bubbles. Using He reaction rate model in W, we investigate the effect of temperature on the growth and surface bursting of He nano-bubbles under low-energy (100 eV) and large-flux (∼1022/m2⋅s) He+ irradiations. Increasing the irradiation temperature from 750 to 2500 K leads to a significant change in both the radius of He nano-bubbles and He retention. At an elevated temperature, He solute atoms prefer to rapidly diffuse into He nano-bubbles, thus affecting their concentration, growth and surface bursting. The decrease in He retention is attributed to an increase in the hop rate of solute He atoms in the W top layer, resulting in the significant He release from the W surface. The radius and density of He nano-bubbles calculated by our model are consistent with our experimental observation.

Zeitschriftenartikel

X. Li
H. Fan
W. Liu
Y. Cui
C. Niu
W. Ni
Y. Zhang
S. Dai
Günther Benstetter
G. Lei
D. Liu

The heat flux and temperature distribution of W fuzz layers under fusion-relevant He/D ion irradiations.

In: Journal of Nuclear Materials (vol. 557) , pg. 153319

(2021)

DOI: 10.1016/j.jnucmat.2021.153319

Abstract anzeigen

The thermal diffusion of nanostructured W fuzz layers formed over W divertor targets due to fusion-relevant He+ irradiations remain unclear so far. By analyzing the collision process of energetic He+ and D+ ions in the fuzz layers, we have calculated the temperature distribution and heat flux of fuzz layers under low-energy (10–200 eV) and high-flux (1022–1025/m2⋅s) He+/D+ irradiations. Both the heat flux of fuzz layers and the temperature difference () between the top and bottom of fuzz layers are determined by the radius of W nanofibers, the thickness of fuzz layers, and the heat load over W targets. Our simulation predicts that under fusion-relevant He+/D+ irradiations at the energy of < 100 eV and the flux of < 1.0 × 1024/m2⋅s, is lower than 35 K when the heat load over the divertor varies in the range of < 10 MW/m2. Under the fusion-relevant He+/D+ irradiations, the heat flux of nanostructured fuzz layers is about 13–19% of the extremely high heat load over the W targets, indicating that the fuzz layers over W divertor targets can be very important for decreasing the extremely high heat load, such as type – I edge localized modes in the fusion device.

Zeitschriftenartikel

Christoph Metzke
Fabian Kühnel
Jonas Weber
Günther Benstetter

Scanning Thermal Microscopy of Ultrathin Films: Numerical Studies Regarding Cantilever Displacement, Thermal Contact Areas, Heat Fluxes, and Heat Distribution.

In: Nanomaterials (vol. 11) , pg. 491

(2021)

DOI: 10.3390/nano11020491

Abstract anzeigen

New micro- and nanoscale devices require electrically isolating materials with specific thermal properties. One option to characterize these thermal properties is the atomic force microscopy (AFM)-based scanning thermal microscopy (SThM) technique. It enables qualitative mapping of local thermal conductivities of ultrathin films. To fully understand and correctly interpret the results of practical SThM measurements, it is essential to have detailed knowledge about the heat transfer process between the probe and the sample. However, little can be found in the literature so far. Therefore, this work focuses on theoretical SThM studies of ultrathin films with anisotropic thermal properties such as hexagonal boron nitride (h-BN) and compares the results with a bulk silicon (Si) sample. Energy fluxes from the probe to the sample between 0.6 µW and 126.8 µW are found for different cases with a tip radius of approximately 300 nm. A present thermal interface resistance (TIR) between bulk Si and ultrathin h-BN on top can fully suppress a further heat penetration. The time until heat propagation within the sample is stationary is found to be below 1 µs, which may justify higher tip velocities in practical SThM investigations of up to 20 µms−1. It is also demonstrated that there is almost no influence of convection and radiation, whereas a possible TIR between probe and sample must be considered.

Beitrag in Sammelwerk/Tagungsband

Günther Benstetter
Jonas Weber
Fabian Kühnel
Christoph Metzke

Hochwärmeleitfähige ultradünne Schichten für die Elektronik der Zukunft – Projekt AlhoiS. Thermische und elektrische Charakterisierung dünner Schichten.

Deggendorf pg. 110-114

(2021)

Zeitschriftenartikel

W. Ni
C. Niu
Y. Zhang
L. Liu
Y. Cui
H. Fan
D. Liu
Günther Benstetter
G. Lei

Modeling W fuzz growth over polycrystalline W due to He ion irradiations at an elevated temperature.

In: Journal of Nuclear Materials (vol. 550) , pg. 152917

(2021)

DOI: 10.1016/j.jnucmat.2021.152917

Abstract anzeigen

Based on the physical processes, such as the collisions of energetic He ions in a fuzz layer, He+ implantations into W bulk, and surface erosion of W fuzz layer, we have modeled the growth of W fuzz layer over polycrystalline W targets under fusion-relevant He/D ion irradiations. From this modeling, we have found that the W fuzz growth results from He+ implantations into W bulk beneath the fuzz layer, and their subsequent erosion into W bulk. The fast-growing, slow-growing, and equilibrium regions are clearly observed during the growth of fuzz layer. In the equilibrium region, the maximum fuzz layer thickness is formed while the rate of W fuzz growth resulting from He+ implantations into W bulk is quite close to the erosion rate. Our study shows that the W fuzz layer with a large surface-to-volume ratio provides an entire protection against the He+ erosion into W bulk. In this study, we have predicted the maximum fuzz layer thickness at the fusion-relevant He+ dose of ~1030/m2, which is strongly dependent on the free distance of He+ ions in fuzz layer and the surface erosion yield of fuzz layer.

Zeitschriftenartikel

Y. Zhang
H. Fan
C. Niu
Y. Cui
W. Ni
W. Liu
Günther Benstetter
G. Lei
D. Liu

He nanobubble driven W surface growth during low-energy He ion irradiations.

In: Journal of Nuclear Materials (vol. 554) , pg. 153073

(2021)

DOI: 10.1016/j.jnucmat.2021.153073

Abstract anzeigen

By using scanning electron microscopy and atomic force microscopy, we observe the microscopic surface evolution of W crystals exposed to low-energy (50 eV) He+ irradiations at the temperature of 1050 K. We find that the He+ irradiation leads to the growth and emergence of nanoscale undulations over W (110), and the surface regions with less undulations are dominating the microscopic evolution of W crystals. Analysis shows that the thermodynamic instability of W crystals irradiated is attributed to the He nanobubble driven W surface growth, which has been confirmed by our experimental measurements and He reaction rate model in W. Our study will play a crucial role in understanding the growth process of undulating surface microstructures under fusion-relevant He+ irradiations.

Zeitschriftenartikel

Fabian Kühnel
Jonas Weber
Christoph Metzke
Günther Benstetter

Thermo reflectance imaging re-imagined. A low-cost alternative for determining thermal conductivity.

In: Wiley Analytical Science

(2021)

Abstract anzeigen

The thermal conductivity of thin films plays a central role in the development of new microelectronic components. If the heat generated in such components cannot be properly dissipated, hot spots form which can lead to component failure. However, determining thermal conductivities, especially in thin films, involves some effort and cost. In the field of processor and graphics card development, manufacturers are engaged in a fierce race to bring the most powerful product onto the market. This requires ever smaller transistors. In the meantime, the production process required for this has reached a size of 2 nm [1]. With increasing miniaturisation, the power density increases and thus also the generated heat. If this heat cannot dissipate effectively, the component fails. This is a decisive reason why the investigation of the thermal conductivity of thin films is becoming increasingly important. For the investigation of thermal conductivity there are a variety of measuring methods, such as the laser-flash method, the Micro-Raman method, the Scanning Thermal Microscopy, the 3-Omega method or the thermo-reflectance imaging method. As different as all these methods are, they have one thing in common: they are extremely complex and require very expensive equipment.

Zeitschriftenartikel

K. Hollstein
D. Entholzner
G. Zhu
K. Weide-Zaage
Günther Benstetter

Developing a micro-thermography system for thermal characterization of LED packages.

In: Microelectronic Engineering (vol. 254) , pg. 111694

(2022)

DOI: 10.1016/j.mee.2021.111694

Abstract anzeigen

LED system design is often limited by the thermal performance of the system. Increased temperatures can cause a decrease in optical performance and can lower the overall reliability of the system. Therefore, proper thermal management and design is crucial for the device performance. Accurately measuring the junction temperature of a LED die is a complicated task. This paper is focusing on the application of micro-thermography for measuring the resulting surface temperature of a bare die bonded on a PCB substrate. First, relevant literature about thermal management of LED systems and standard approaches for junction temperature measurements are given. Then, the thermography system is introduced, and the implementation of the measurement procedure is discussed. The emissivity correction is an important part of the calibration of the system and is described in detail. A thorough thermal analysis has been conducted using the novel micro-thermography approach and the results are used for determining the thermal resistance of the system under analysis. Furthermore, a thermal simulation has been conducted using Finite Element Modeling. The model and meshing are described, and initial simulation results are given. The experimental data is then used to modify the thermal simulation model to accurately represent the thermal behavior of the system.

Zeitschriftenartikel

Fabian Kühnel
Christoph Metzke
Jonas Weber
J. Schätz
G. Duesberg
Günther Benstetter

Investigation of Heater Structures for Thermal Conductivity Measurements of SiO2 and Al2O3 Thin Films Using the 3-Omega Method.

In: Nanomaterials (vol. 12)

(2022)

DOI: 10.3390/nano12111928

Abstract anzeigen

A well-known method for measuring thermal conductivity is the 3-Omega (3ω) method. A prerequisite for it is the deposition of a metal heater on top of the sample surface. The known design rules for the heater geometry, however, are not yet sufficient. In this work, heaters with different lengths and widths within the known restrictions were investigated. The measurements were carried out on SiO2 thin films with different film thicknesses as a reference. There was a significant difference between theoretical deposited heater width and real heater width, which could lead to errors of up to 50% for the determined thermal conductivity. Heaters with lengths between 11 and 13 mm and widths of 6.5 µm or more proved to deliver the most trustworthy results. To verify the performance of these newfound heaters, additional investigations on Al2O3 thin films were carried out, proving our conclusions to be correct and delivering thermal conductivity values of 0.81 Wm-1 K-1 and 0.93 Wm-1 K-1 for unannealed and annealed samples, respectively. Furthermore, the effect of annealing on Al2O3 was studied, revealing a significant shrinking in film thickness of approximately 11% and an increase in thermal conductivity of 15%. The presented results on well-defined geometries will help to produce optimized heater structures for the 3ω method.

Zeitschriftenartikel

Yang Zhang
Xiaoping Li
Chunjie Niu
Yunqiu Cui
Weiyuan Ni
Günther Benstetter
Guangjiu Lei
Dongping Liu
Wenchun Wang

W nano-fuzz growth by high-flux He ion irradiation with their energy above 300 eV.

In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms (vol. 520) , pg. 22-28

(2022)

DOI: 10.1016/j.nimb.2022.04.002

Abstract anzeigen

Here experiments are designed to evaluate the effects of >300 eV He+ energy and temperature on the W nano-fuzz growth over W targets. Our measurements show that increasing He+ energy from 300 eV to 750 eV leads to an increase in the W sputtering yield, thus a decrease in the thickness of W fuzz layers. Under the 750 eV He+ irradiation, the growth of W fuzz layers over W targets is not obvious due to the He+ sputtering. The irradiation temperature varying in the range of 1300 K – 1600 K is most suitable for W fuzz growth by high-flux He+ irradiation over W targets. Our analysis indicates that the deposition of sputtered W atoms onto the neighboring W nano-fibers leads to an increase in their diameter, thus affecting the W fuzz growth. When the irradiation temperature varies from 1900 K to 2700 K, the thermodynamic instability of W nano-fibers, which are metastable can be greatly increased, resulting in their shrinkage.

Vortrag

Jonas Weber
Günther Benstetter
Fabian Kühnel
Christoph Metzke
M. Lanza
D. Liu

Advances in Combined Mechanical and Electrical SPM Characterization of Thin Films. Poster presentation.

Charles University Prague.

Prague, Czech Republic 08.-10.06.2022.

(2022)

Vortrag

Günther Benstetter

Advances in combined mechanical and electrical SPM characterization of thin films..

Prag, Tschechische Republik 08.-10.06.2022.

(2022)

Zeitschriftenartikel

Jonas Weber
Y. Yuan
S. Pazos
Fabian Kühnel
Christoph Metzke
J. Schätz
Werner Frammelsberger
Günther Benstetter
M. Lanza

Current-Limited Conductive Atomic Force Microscopy.

In: ACS Applied Materials & Interfaces

(2023)

DOI: 10.1021/acsami.3c10262

Abstract anzeigen

Conductive atomic force microscopy (CAFM) has become the preferred tool of many companies and academics to analyze the electronic properties of materials and devices at the nanoscale. This technique scans the surface of a sample using an ultrasharp conductive nanoprobe so that the contact area between them is very small (<100 nm2) and it can measure the properties of the sample with a very high lateral resolution. However, measuring relatively low currents (∼1 nA) in such small areas produces high current densities (∼1000 A/cm2), which almost always results in fast nanoprobe degradation. That is not only expensive but also endangers the reliability of the data collected because detecting which data sets are affected by tip degradation can be complex. Here, we show an inexpensive long-sought solution for this problem by using a current limitation system. We test its performance by measuring the tunneling current across a reference ultrathin dielectric when applying ramped voltage stresses at hundreds of randomly selected locations of its surface, and we conclude that the use of a current limitation system increases the lifetime of the tips by a factor of ∼50. Our work contributes to significantly enhance the reliability of one of the most important characterization techniques in the field of nanoelectronics.

Zeitschriftenartikel

Jonas Weber
Y. Yuan
Fabian Kühnel
Christoph Metzke
J. Schätz
Werner Frammelsberger
Günther Benstetter
M. Lanza

Solid Platinum Nanoprobes for Highly Reliable Conductive Atomic Force Microscopy.

In: ACS Applied Materials & Interfaces (vol. 15) , pg. 21602-21608

(2023)

DOI: 10.1021/acsami.3c01102

Abstract anzeigen

Conductive atomic force microscopy (CAFM) is a powerful technique to investigate electrical and mechanical properties of materials and devices at the nanoscale. However, its main challenge is the reliability of the probe tips and their interaction with the samples. The most common probe tips used in CAFM studies are made of Si coated with a thin (∼20 nm) film of Pt or Pt-rich alloys (such as Pt/Ir), but this can degrade fast due to high current densities (>102A/cm2) and mechanical frictions. Si tips coated with doped diamond and solid doped diamond tips are more durable, but they are significantly more expensive and their high stiffness often damages the surface of most samples. One growing alternative is to use solid Pt tips, which have an intermediate price and are expected to be more durable than metal-coated silicon tips. However, a thorough characterization of the performance of solid Pt probes for CAFM research has never been reported. In this article, we characterize the performance of solid Pt probes for nanoelectronics research by performing various types of experiments and compare them to Pt/Ir-coated Si probes. Our results indicate that solid Pt probes exhibit a lateral resolution that is very similar to that of Pt/Ir-coated Si probes but with the big advantage of a much longer lifetime. Moreover, the probe-to-probe deviation of the electrical data collected is small. The use of solid Pt probes can help researchers to enhance the reliability of their CAFM experiments.

Zeitschriftenartikel

K. Zhu
S. Pazos
F. Aguirre
Y. Shen
Y. Yuan
W. Zheng
O. Alharbi
M. Villena
B. Fang
X. Li
A. Milozzi
M. Farronato
M. Muñoz-Rojo
T. Wang
R. Li
H. Fariborzi
J. Roldan
Günther Benstetter
X. Zhang
H. Alshareef
T. Grasser
H. Wu
D. Ielmini
M. Lanza

Hybrid 2D–CMOS microchips for memristive applications.

In: Nature (vol. 618) , pg. 57-62

(2023)

DOI: 10.1038/s41586-023-05973-1

Abstract anzeigen

Exploiting the excellent electronic properties of two-dimensional (2D) materials to fabricate advanced electronic circuits is a major goal for the semiconductors industry1-2. However, most studies in this field have been limited to the fabrication and characterization of isolated large (>1µm2) devices on unfunctional SiO2/Si substrates. Some studies integrated monolayer graphene on silicon microchips as large-area (>500µm2) interconnection3 and as channel of large transistors (~16.5µm2)4-5, but in all cases the integration density was low, no computation was demonstrated, and manipulating monolayer 2D materials was challenging because native pinholes and cracks during transfer increase variability and reduce yield. Here we present the fabrication of high-integration-density 2D/CMOS hybrid microchips for memristive applications - CMOS stands for complementary metal oxide semiconductor. We transfer a sheet of multilayer hexagonal boron nitride (h-BN) onto the back-end-of-line (BEOL) interconnections of silicon microchips containing CMOS transistors of the 180nm node, and finalize the circuits by patterning the top electrodes and interconnections. The CMOS transistors provide outstanding control over the currents across the h-BN memristors, which allows us to achieve endurances of ~5 million cycles in memristors as small as ~0.053µm2. We demonstrate in-memory computation by constructing logic gates, and measure spike-timing dependent plasticity (STDP) signals that are suitable for the implementation of spiking neural networks (SNN). The high performance and the relatively-high technology readiness level achieved represent a significant advance towards the integration of 2D materials in microelectronic products and memristive applications.

Labore

Wafertest

Campus Deggendorf

Sustainable Production & Energy Technologies

Rasterelektronen- und Laser-Scanning Mikroskopie

Campus Deggendorf

Sustainable Production & Energy Technologies

Raster-Sonden-Mikroskopie (RSM)

Campus Deggendorf

Sustainable Production & Energy Technologies

Elektronische Bauelemente

Campus Deggendorf

Sustainable Production & Energy Technologies

Projekte

mehrere Projekte in den Bereichen Oberflächenanalytik, thermische und elektrische Charakterisierung neuer Materialien, >20 abgeschlossene Projekte

Labore

Elektronische Bauelemente, Raster-Sonden-Mikroskopie (RSM), Raster-Elektronen-Mikroskopie (REM) und Halbleiteranalytik

Kernkompetenzen

Material- und Oberflächenanalytik

* Raster-Elektronen-Mikroskopie & begleitende Methoden

Röntgenanalytik (EDX, WDX), Gefüge- und Strukturanalytik (EBSD), Mikro-Röntgenfluoreszenz (μ-XRF) Raster-Transmissions-Elektonenmikroskopie (STEM), korrelative Mikroskopie

* Raster-Sonden-Mikroskopie & Laser-Scanning Mikroskopie

kombinierte mechanische, magnetische, elektrische, thermische und chemische Mikro-Charakterisierung

* Thermische Charakterisierung

Qualitätssicherung und Zuverlässigkeitsanalytik

Fehler- und Ausfallanalytik, Wafer-Level-Zuverlässigkeitsanalytik, HL-Lebensdauer-Untersuchungen

Vita

Akademischer Werdegang

Berufung: Professor, Technische Hochschule Deggendorf, 1998 Promotion: Dr.-Ing., TU München, 1994 Studienabschluss: Dipl.-Ing. Elektrotechnik, 1989

Beruflicher Werdegang

1989-1994: Wissenschaftlicher Assistent, TU München 1994-1998: Siemens HL, IBM/Siemens/Toshiba DRAM – Projekt in Burlington, Vermont, USA seit 1998: Professor an der Technischen Hochschule Deggendorf, Fakultät Elektrotechnik und Medientechnik, Leiter des Insituts für für Qualitäts- und Materialanalysen (IQMA)

Sonstiges

Associate Editor von Microelectronic Engineering (Elsevier)