Papers by Keyword: NO Annealing

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Authors: W. Wang, S. Banerjee, T. Paul Chow, Ronald J. Gutmann
Authors: Hiroshi Yano, Tomoaki Hatayama, Yukiharu Uraoka, Takashi Fuyuki
Authors: Dai Okamoto, Hiroshi Yano, Tomoaki Hatayama, Yukiharu Uraoka, Takashi Fuyuki
Abstract: This paper describes the influence of the geometric component in the charge-pumping measurement of 4H-SiC MOSFETs. Charge-pumping measurements were conducted on 4H-SiC MOSFETs with and without NO annealing. Charge-pumping measurements with different pulse-fall times revealed that the geometric component exists in 4H-SiC MOSFETs and is especially large in the unannealed MOSFETs. A sufficiently long fall-time is needed to minimize its effect, which is expected to be 1–10 μs for 4H-SiC MOSFETs with a gate length of 10 μm.
Authors: C.Y. Lu, James A. Cooper, G.Y. Chung, John R. Williams, K. McDonald, Leonard C. Feldman
Authors: Ayayi Claude Ahyi, S.R. Wang, John R. Williams
Abstract: The effects of gamma radiation on field effect mobility and threshold voltage have been studied for lateral n-channel 4H-SiC MOSFETs passivated with nitric oxide. MOS capacitors (n and p) and n-channel lateral MOSFETs were irradiated unbiased (floating contacts) for a total gamma dose of 6.8Mrad (Si). The MOS capacitors were used to study the radiation-induced interface traps and fixed oxide charge that affect the performance of the MOSFETs. Radiationinduced interface traps were observed near the SiC valence band edge and just above mid-gap, and field effect channel mobility was reduced by 18-20% following irradiation. Even so, 4HMOSFETs appear to be more radiation tolerant than Si devices.
Authors: Hiroshi Yano, Tomoaki Hatayama, Yukiharu Uraoka, Takashi Fuyuki
Abstract: High temperature (1250 oC) NO annealing was performed for deposited oxide (SiO2) and oxynitride (SiON) films on n-type 4H-SiC. Interface state density of SiO2 samples was dramatically reduced (one order of magnitude) by NO annealing compared to N2 annealing, resulting in 1x1011 cm-2eV-1 at 0.2 eV below the conduction band edge. In contrast, that of NO annealed SiON samples showed only 30% decrease and was still in the range of 1x1012 cm-2eV-1. These different effects of NO annealing against SiO2 and SiON are probably due to different reaction mechanism at the interface. Breakdown field of SiO2 samples annealed in NO was as high as 10 MV/cm. Barrier height of this sample was 2.86eV, which is close to the ideal value.
Authors: John Rozen, Sarit Dhar, San Wu Wang, Valeri V. Afanas'ev, Sokrates T. Pantelides, John R. Williams, Leonard C. Feldman
Abstract: We report on the effect of nitridation on the negative and positive charge buildup in SiC gate oxides during carrier injection. We observe that the incorporation of nitrogen at the SiO2/SiC interface can enhance the reliability of the interface by suppressing the generation of interface states upon electron injection but that it can also degrade the oxide by creating additional hole traps. We relate these phenomena to the passivation of atomic-level defects by nitrogen.
Authors: Hiroshi Yano, Tsuyoshi Araoka, Tomoaki Hatayama, Takashi Fuyuki
Abstract: Effects of combination of NO and POCl3 annealing on electrical properties and their stability of 4H-SiC MOS capacitors and MOSFETs were investigated. Channel mobility of MOSFETs processed with both NO and POCl3 annealing did not exceed that of POCl3 annealed MOSFETs. As for the stability of flat-band voltage and threshold voltage using a constant field stress test, the combined annealed sample indicated very stable characteristics compared with single annealed devices with NO or POCl3. The reason for obtaining stable electrical properties is discussed based on nitridation and phosphorization effects at the interface.
Authors: Sei Hyung Ryu, Anant K. Agarwal, Jim Richmond, Mrinal K. Das, Lori A. Lipkin, John W. Palmour, N.S. Saks, John R. Williams
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