Improved Gate Reliability of p-GaN Gate HEMTs by Gate Doping Engineering

TL;DR

This paper introduces a doping engineering technique in p-GaN gate HEMTs that reduces electric field stress, suppresses leakage, and significantly enhances gate breakdown voltage and reliability without extra fabrication steps.

Contribution

The study presents a novel doping engineering approach with an additional GaN layer to improve gate reliability and increase operating voltage margin of p-GaN gate HEMTs.

Findings

Gate breakdown voltage increased from 10.6 V to 14.6 V.

Maximum gate drive voltage for 10-year lifetime increased from 6.2 V to 10.6 V.

Gate leakage current was suppressed.

Abstract

We present a novel p-GaN gate HEMT structure with reduced hole concentration near the Schottky interface by doping engineering in MOCVD, which aims at lowering the electric field across the gate. By employing an additional unintentionally doped GaN layer, the gate leakage current is suppressed and the gate breakdown voltage is boosted from 10.6 to 14.6 V with negligible influence on the threshold voltage and on-resistance. Time-dependent gate breakdown measurements reveal that the maximum gate drive voltage increases from 6.2 to 10.6 V for a 10-year lifetime with a 1% gate failure rate. This method effectively expands the operating voltage margin of the p-GaN gate HEMTs without any other additional process steps.