Effects of oxidation temperature on Ga2O3film thermally grown on GaN

The effects of oxidation temperature on thermally oxidized GaN film were investigated. The GaN wafers were oxidzied at 750°C, 800°C and 850°C respectively. The electrical characteristics and interface quality of MOS capacitors were compared among different oxidation temperatures. The sample oxidized at 800°C presented best current-voltage, capacitance-voltage characteristics and smoothest surface morphology, while the higher oxidation temperature of 850°C gave best interface quality. The electrical breakdown field was increased by one order of magnitude when the sample was oxidized at 800°C as compared with 750°C and 850°C. Lastly, after the sample oxidized at 800°C was annealed at 850°C for 10 min, the quality of its oxide was significantly degraded.