Evidence of GaN HEMT Schottky Gate Degradation After Gamma Irradiation

Abstract

The effects of gamma rays on two kinds of GaN high-electron-mobility transistors (HEMTs) have been investigated in this paper. We have identified a gate degradation using a combination of optical and electrical measurements. We have demonstrated that the channel current under the degradation position is outside of the gate's control. This degradation prevents the gate from fully pinching off the channel, creating a current concentration region when applying a reverse gate voltage. An integrated analysis, including I-V characterization, the emission microscope (EMMI) technique, and temperature-dependent measurements, was applied to study its mechanism. It is attributed to an irradiation-induced degradation in the Schottky contact.