O
Oliver Ambacher
Researcher at Fraunhofer Society
Publications - 862
Citations - 29006
Oliver Ambacher is an academic researcher from Fraunhofer Society. The author has contributed to research in topics: Amplifier & Monolithic microwave integrated circuit. The author has an hindex of 64, co-authored 848 publications receiving 26256 citations. Previous affiliations of Oliver Ambacher include Osram & Siemens.
Papers
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Reliability of AlGaN/GaN HEMTs under DC- and RF-operation
Michael Dammann,M. Casar,Patrick Waltereit,Wolfgang Bronner,Helmer Konstanzer,Rudiger Quay,Stefan Müller,Michael Mikulla,Oliver Ambacher,P.J. van der Wel,T. Rodle,Reza Behtash,F. Bourgeois,K. Riepe +13 more
TL;DR: In this article, the gate processing technology is used to improve the stability of the gate leakage current and the short term drain voltage robustness under off state condition has been examined by a DC-voltage-step-stress test.
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Influence of plasma treatments on the properties of GaN/AlGaN/GaN HEMT structures
Stefanie Linkohr,Wilfried Pletschen,Vladimir Polyakov,Marcel Himmerlich,Pierre Lorenz,Stefan Krischok,Lutz Kirste,Stefan Müller,Oliver Ambacher,Oliver Ambacher,Volker Cimalla +10 more
TL;DR: In this article, the impact of fluorine and nitrogen plasma treatments on the electronic transport properties of GaN/AlGaN/GaN heterostructures by employing different plasma processes and subsequent annealing in nitrogen atmosphere at 425 °C was investigated.
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Photoreflectance Studies of AlGaN/GaN Heterostructures Containing a Polarisation Induced 2DEG
Rüdiger Goldhahn,C. Buchheim,S. Shokhovets,Gerhard Gobsch,Oliver Ambacher,A. Link,M. Hermann,Martin Stutzmann,Y. Smorchkova,Umesh K. Mishra,James S. Speck +10 more
TL;DR: In this article, photoreflectance measurements were carried out to determine the electric field strength within the unintentionally doped barriers of Ga-face polarity Al x Ga 1-x N/GaN heterostructures containing high-mobile polarisation induced 2DEGs.
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Enhanced actuation of nanocrystalline diamond microelectromechanical disk resonators with AlN layers
Taro Yoshikawa,Taro Yoshikawa,Markus Reusch,Markus Reusch,Katarzyna Holc,D. Iankov,D. Iankov,Verena Zuerbig,Agne Zukauskaite,Christoph E. Nebel,Oliver Ambacher,Oliver Ambacher,Vadim Lebedev +12 more
TL;DR: In this paper, a disk resonator with a unimorph (AlN/NCD) structure is fabricated by depositing a c-axis oriented AlN on a capacitive NCD disk Resonator and the unimorph resonator is piezoelectrically actuated with flexural whispering gallery modes with a relatively large electrode gap spacing.
Proceedings ArticleDOI
Reliability and degradation mechanism of 0.25 µm AlGaN/GaN HEMTs under RF stress conditions
Michael Dammann,M. Baeumler,F. Gutle,M. Casar,H. Walcher,Patrick Waltereit,Wolfgang Bronner,Stefan Müller,Rudolf Kiefer,Ruediger Quay,Michael Mikulla,Oliver Ambacher,Andreas Graff,Frank Altmann,M Simon +14 more
TL;DR: In this paper, the reliability and degradation mechanism of AlGaN/GaN single stage amplifiers after 10 GHz stress at a drain voltage of 42 V and channel temperatures above 250°C was investigated using electroluminescence (EL) imaging, infrared thermography, and TEM.