Switching Performance of GaN $p$-FET-bridge (PFB-) HEMTs Studied with Mixed-mode TCAD Simulation

Abstract

This work investigates the performance of PFB-HEMTs during switching transients at a circuit level by means of mixed-mode (device/circuit) TCAD simulation. The PFB-HEMTs have been recently proposed to have a higher threshold voltage ($V_{\text{TH}}$) comparing to conventional Schottky-type $p$-GaN gate HEMTs, by inserting a normally-on $p$-channel FET between the gate and source of a conventional device. In this simulation, it is found that the on-resistance of the $p$-FET should be adequately low to maintain the high $V_{\text{TH}}$ of the PFB-HEMTs during fast switching transients, thus to prevent false turn-on phenomenon. The efficiency of a buck convertor, by replacing the synchronous switch from a conventional device to a PFB-HEMT, increases from 95.2% to 96.7% at 1 MHz.