Remained p-GaN effect to turn-off energy loss (Eoff) in p-GaN gate power devices

In p-GaN gate AlGaN/GaN power devices, the p-GaN etching process to define the gate region is critical to device performance. In some cases, the remained p-GaN in the ungated region can exist as a result of under-etching, and can act like a charge reservoir in the p-GaN gate power device. In this reported work, the effect of this remained p-GaN layer is investigated for the first time. The main effect of the thick remained p-GaN on the ungated region is the increments of turn-off energy loss (E_off) in spite of the similar turn-on energy loss (E_on). This is related to the hole trapping in the remained p-GaN region which is observed by the change of turn-off gate voltages.