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.