Improved operation stability of Al₂O₃/AlGaN/GaN MOS high-electron-mobility transistors grown on GaN substrates

Abstract

This paper presents electrical characterization of Al2O3/AlGaN/GaN metal–oxide–semiconductor (MOS) high-electron-mobility transistors (HEMTs) grown on GaN substrates. The postmetallization annealing (PMA) at 300 °C achieved effective reduction of electronic states at the Al2O3/AlGaN interface, leading to improved gate controllability and current linearity of the MOS HEMTs. The MOS HEMT with PMA showed a subthreshold slope of 68 mV dec−1. In addition, excellent operation stability of the MOS HEMT was observed at high temperatures. Even at 150 °C, the HEMT showed low leakage current of 1.5 × 10−9 A mm−1 and a threshold voltage drift of only 0.25 V from its room temperature value.