Process Dependence of Proton-Induced Degradation in GaN HEMTs

The 1.8-MeV proton radiation responses are compared for AlGaN/GaN HEMTs grown under Ga-rich, N-rich, and NH3-rich conditions. The NH3-rich devices are more susceptible to proton irradiation than the Ga-rich and N-rich devices. The 1/fnoise of the devices increases with increasing fluence. Density functional theory calculations show that N vacancies and Ga-N divacancies lead to enhanced noise in these devices.