Performance Instability of 650 V p-GaN Gate HEMT Device under Temperature-related Positive Gate Bias Stresses

In this work, the effects of positive gate stresses on threshold voltage (Vth) and on-state resistance (Ron) instability of the 650 V Schottky p-GaN gate HEMT devices were investigated under different gate bias stresses and a wide temperature range. It is noticed that once the stress was applied, there was an immediate Vth jump. The drift magnitude and direction of Vth and Ron during the stressing tests were largely dependent on the applied Vgs bias. The temperature had a significant impact on static parameters. The variations in Vth (DeltaVth) demonstrated an overall decreasing trend with the progress of experiment under the positive gate stress of 6 V. The initial DeltaVth jump increased with temperature at first and then reduced at certain temperatures. The variation in Ron (DeltaRon) caused by the positive gate bias of 6 V was minor at temperatures below zero, but it became more pronounced with the increase in temperature.