Highly suppressed interface traps of Al2O3/GaN through interposing a stoichiometric Ga2O3layer

Abstract

Al2O3 is a broadly employed dielectric material in GaN high electron mobility transistors. Nevertheless, at the Al2O3/GaN interface, numerous traps induced by nonidealities of the native GaO x layer on the surface of GaN can lead to threshold voltage instability and other reliability issues. In this study, after removing the native GaO x layer, a stoichiometric Ga2O3 layer was sandwiched between Al2O3 and GaN. The interfacial state density of Al2O3/GaN can be reduced by more than two orders of magnitude to an extremely low level of 2.4 × 1010 eV-1 cm-2 at the energy level of 0.36 eV.