Performance Instability of 650 V p-GaN Gate HEMTs under Temperature-Induced Negative Gate Bias Stresses

In this article, the effect of negative gate bias stress and temperature on threshold voltage (Vth) and on-state resistance (Ron) instability of 650 V Schottky p-GaN gate HEMT devices from different manufacturers was explored. It is found that the there was an immediate Vth drift once the device was stressed. With the decrease in the negative gate voltage (Vgs), the variation in Vth (∆Vth) and the variation in R on (∆Ron) became more significant. The measuring Vgs also played an important role when the testing Vgs was low. The low temperature can lead to the constant increment in ∆Vth , while ∆Vth decreased and then increased at elevated temperatures. The trapping/de-trapping speeds of electrons and holes were enhanced with temperature. The substantial increase in ∆Ron at high temperatures can increase the loss of devices to a great extent. The instability of the static performances of Schottky p-GaN gate HEMT devices are harmful to the real application.