High Performance AlGaN/GaN HEMT Switches Employing 500°C Oxidized Ni/Au Gate for Very Low Leakage Current and Improvement of Uniformity

The electrical characteristics of HEMT such as leakage current and breakdown voltage were improved considerably by oxidation of Ni/Au Schottky gate of HEMT. Leakage current was decreased from 4.2muA to 3.3nA and uniform high breakdown voltage of ~480V was obtained with floating gate. On-resistance was also decreased from 4.32mOmega-cm 2 to 3.89mOmega-cm 2 when oxidation time was 5min due to the improvement of the 2DEG which was increased from 7.82times10 12 /cm 2 to 9.61times10 12 /cm 2 . Our experimental results show that oxidation of Ni/Au Schottky gate which is rather simple may be suitable for improvement of AlGaN/GaN HEMT