Numerical analysis of high-voltage RESURF AlGaN/GaN high-electron-mobility transistor with graded doping buffer and slant back electrode

摘要

A reduced surface field (RESURF) AlGaN/GaN high-electron-mobility transistor (HEMT) with graded doping buffer (GDB) and slant back electrode (SBE) is proposed. In the GDB, the p-dopant density increases linearly both from top to bottom and right to left. The concentrated negative space charges in the lower-left corner of GDB attract the electric field lines from the channel and barrier towards the gate under OFF-state, which flats the electric field and enhances the breakdown voltage (V-br). Additionally, the low p-dopant density near the top of GDB achieves the device with low ON-state resistance (R-ON). The SBE flats the electric field along the channel above it and introduces a peak electric field near its edge. Simulation results show a V-br of 2150 V and R-ON of 7.05 Omega mm for the proposed device, compared with 1701 V and 7.73 Omega mm for the conventional back electrode RESURF HEMT (BE-RESURF HEMT) with the same gate -drain spacing. Moreover, due to the reduced depletion of 2DEG from the GDB, the proposed device shows slight increases in f(T) and f(max) (8.76 and 14.80 GHz), comparing with the conventional BE-RESURF HEMT (8.24 and 13.84 GHz).