Effects of air annealing on DC characteristics of InAlN/GaN MOS high-electron-mobility transistors using atomic-layer-deposited Al₂O₃

Abstract

We evaluated the DC characteristics of InAlN/GaN metal–oxide–semiconductor high-electron-mobility transistors (MOS-HEMTs) using atomic-layer-deposited (ALD-)Al2O3 by focusing on air annealing to control defect levels in Al2O3 and electronic states at the Al2O3/InAlN interface. We clarified that the transconductance linearity and subthreshold slope were improved by air annealing, indicating a reduction in the number of electronic states at the Al2O3/InAlN interface. Furthermore, the cathodoluminescence study demonstrated that the oxygen-related defects in ALD-Al2O3 were decreased by air annealing. Consequently, we could successfully reduce the threshold voltage shift of InAlN/GaN MOS-HEMTs by using air-annealed ALD-Al2O3.