Analysis and simulation of bulk polarization mechanism in p-GaN HEMT with AI component gradient buffer layer

Abstract

In this paper,bulk polarization mechanism and radiation simulation of the Al component gradient buffer layer (GBL) and constant buffer layer (CBL) of p-GaN HEMT (p-GaN GBL-HEMT and p-GaN CBL-HEMT) are analyzed and studied. It is found that the p-GaN GBL-HEMT can significantly reduce the buffer leakage current. The linear gradient amplitude (the range of linear gradients of Al components vertically in the buffer) of 20~30% Al components can significantly increase the breakdown voltage (VBK) of the device, up to 1312V. Simultaneously, although the p-GaN GBL-HEMT reduces the 2DEG concentration, the device still has a specific on-resistance (RON,sp) and drain saturation current (IDS,sat) equivalent to the p-GaN CBL-HEMT due to the conductivity modulation effect. Its Baliga figure of merit is up to 2.27 GW/cm2. Finally, through the SEE simulation and the bulk polarization mechanism analysis, it is found that the drain transient current (IDS,trans) by the identical incident particles in the p-GaN GBL-HEMT is lower than that in the p-GaN CBL-HEMT, and the IDS,trans decreases with the increase of the Al components gradient amplitude. Therefore, the p-GaN GBL-HEMT provides a new idea for improving the electrical performance and SEE hardening.