Investigation on the Long-Term Reliability of High-Voltage p-GaN HEMT by Repetitively Transient Overcurrent

Abstract

In this paper, the effects of repetitively transient overcurrent on the long-term reliability of commercial p-GaN high-electron-mobility transistors (HEMTs) are investigated by using RLC pulse-ring-down tests. The devices rated for 650 V/30 A are electrically stressed by peak pulse currents of 90 A, corresponding to $3\times $ of the given rating. It is found that the device ON-state resistance ( ${R}_{ \mathrm{\scriptscriptstyle ON}}$ ) increases by about 20.7% for the device pulsed 500 000 times. The measured results reveal that the reason for the increase in ${R}_{ \mathrm{\scriptscriptstyle ON}}$ is the traps caused by thermal stress concentration during repetitive pulse process. Furthermore, for the device pulsed with larger than 500 000 times, a conductive path is formed through passivation layer because of trap accumulation, which results in a saturation trend in ${R}_{ \mathrm{\scriptscriptstyle ON}}$ and a remarkably increase in the drain leakage current ( ${I}_{\text {DL}}$ ). However, the high peak currents and large pulse numbers required to produce severe degeneration demonstrate the GaN-based HEMTs have a promising long-term reliability in power switching applications that are susceptible to pulse overcurrent.