Time evolution of electrical degradation under high-voltage stress in GaN high electron mobility transistors

In this work, we investigate the time evolution of electrical degradation of GaN high electron mobility transistors under high voltage stress in the OFF state. We found that the gate current starts to degrade first, followed by degradation in current collapse and eventually permanent degradation in I_D. We also found that the time evolution of gate current degradation is unaffected by temperature, while drain current degradation is thermally accelerated.