High Gate Reliability and Breakdown Voltage p-GaN HEMTs Based on Post-Annealing-Free Oxygen Plasma Treatment

This work presents an enhancement-mode (E-mode) p-GaN HEMT that significantly improves gate reliability and breakdown voltage through a post-annealing-free oxygen plasma treatment (GOPT). This method forms a GaOxN1x interfacial layer beneath the gate metal, increasing the gate breakdown voltage from 13.8 V to 24.8 V and reducing the gate leakage current by three orders of magnitude at VGS=8 V, compared to conventional Schottky p-GaN gates. Time-dependent gate breakdown (TDGB) testing predicts a maximum safe operating gate voltage of 9.2 V for a 10-year lifetime with a 63% failure probability. The fabricated GOPT p-GaN HEMTs show excellent off-state drain breakdown performance, with a voltage of up to 2940 V at a gate-to-drain distance of 28 5m. This approach offers a simplified fabrication process with superior performance in both gate reliability and high-voltage capability, establishing GOPT p-GaN HEMTs as a promising candidate for highperformance, high-reliability power electronics.