Defect and Impurity-Center Activation and Passivation in Irradiated AlGaN/GaN HEMTs

Donor-like defects are activated and acceptor-like defects are passivated when commercial AlGaN/GaN high electron mobility transistors (HEMTs) are irradiated with 10-keV X-rays or 1.8-MeV protons at low fluence. Displacement-damage-induced creation of acceptor-like defects is observed at higher proton fluences. The dehydrogenation of FeGa-H and \text{O}_{\mathrm {N}} -H substitutional impurities and generation of N-vacancy-related defects most likely account for the modest degradation of these devices at high proton fluences. Low-frequency (LF) noise measurements identify FeGa defects as prominent generation-recombination (G-R) centers in these devices. These results enable recalibration of the Dutta-Horn model of LF noise and increased insight into the defect identities and energy distributions in AlGaN/GaN HEMTs.