A novel high breakdown voltage and high switching speed GaN HEMT with p-GaN gate and hybrid AlGaN buffer layer for power electronics applications*

Abstract

A novel p-GaN gate GaN high-electron-mobility transistor (HEMT) with an AlGaN buffer layer and hybrid dielectric zone (H-HEMT) is proposed. The hybrid dielectric zone is located in the buffer and composed of horizontal arranged HfO2 zone and SiN x zone. The proposed H-HEMT is numerically simulated and optimized by the Silvaco TCAD tools (ATLAS), and the DC, breakdown, C–V and switching properties of the proposed device are characterized. The breakdown voltage of the proposed HEMT is significantly improved with the introduction of the hybrid dielectric zone, which can effectively modulate the electric field distribution in the GaN channel and the buffer. High breakdown voltage of 1490 V, low specific on-state resistance of 0.45 mΩ⋅cm2 and high Baliga’s figure of merit (FOM) of 5.3 GW/cm2, small R on Q oss of 212 mΩ⋅nC, high turn-on speed 627 V/ns and high turn-off speed 87 V/ns are obtained at the same time with the gate-to-drain distance L gd of 6 μm.