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Oxidation Process of GaN Schottky Diode for High-Voltage Applications

고전압 응용분야를 위한 GaN 쇼트키 다이오드의 산화 공정

  • Received : 2011.09.08
  • Accepted : 2011.11.19
  • Published : 2011.12.01

Abstract

1 kV high-voltage GaN Schottky diode is realized using GaN-on-Si template by oxidizing Ni-Schottky contact. The Auger electron spectroscopy (AES) analysis revealed the formation of $NiO_x$ at the top of Schottky contact. The Schottky contact was changed to from Ni/Au to Ni/Ni-Au alloy/Au/$NiO_x$ by oxidation. Ni diffusion into AlGaN improves the Schottky interface and the trap-assisted tunneling current. In addition, the reverse leakage current and the isolation-leakage current are efficiently suppressed by oxidation. The isolation-leakage current was reduced about 3 orders of magnitudes. The reverse leakage current was also decreased from 2.44 A/$cm^2$ to 8.90 mA/$cm^2$ under -100 V-biased condition. The formed group-III oxides ($AlO_x$ and $GaO_x$) during the oxidation is thought to suppress the surface leakage current by passivating surface dangling bonds, N-vacancies and process damages.

Keywords

GaN;AlGaN;Schottky diode;Power device;Oxidation

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Acknowledgement

Supported by : 한국 에너지 기술평가원 (KETEP)