Stability of submicron AlGaN/GaN HEMT devices irradiated by gamma rays

AlGaN/GaN high electron mobility transistors (HEMTs) with 0.75@mm gate-length and incorporated C-doped GaN buffer layers have been exposed to gamma radiation. The devices have been irradiated to cumulative doses up to 10^7 rad. The effect of gamma irradiation on the direct current (DC) and low-frequency noise properties of these devices have been investigated in reference to the unexposed device. The DC and noise characteristics show deteriorating device performance upon the gamma exposure. However, some DC parameters, such as transconductance, tended to recover after the irradiation. The gate leakage current and low-frequency noise power spectra indicate this trend even couple of months after the irradiation.