Performance of an AIGaN/GaN MISHEMT with sodium beta-alumina for gate insulation and surface passivation

An AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistor(MISHEMT), with sodium beta-alumina(SBA) for both gate insulation and surface passivation, was investigated and compared with a conventional metal-semiconductor high-electron-mobility transistor(MESHEMT). The measured gate leakage current of the MISHEMT was reduced by approximately one order of magnitude as compared with that of the conventional MESHEMT. The saturation drain current of the AlGaN/GaN MISHEMT reached 830 mA/mm, which was about 43% higher than that of a conventional MESHEMT. The peak extrinsic transconductance of the MISHEMT was 103 mS/mm, which was similarly higher than that of the MESHEMT. The results suggested that the SBA thin film is an effective candidate gate dielectric for AlGaN/GaN MISHEMTs.