Highly suppressed interface traps of Al2O3/GaN through interposing a stoichiometric Ga2O3 layer

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 x 10(10) eV(-1) cm(-2) at the energy level of 0.36 eV.