Effects of Applied Bias and High Field Stress on the Radiation Response of GaN/AlGaN HEMTs

摘要

The sensitivity of GaN/AlGaN HEMTs to 1.8 MeV proton irradiation is greatly enhanced by biasing the devices during irradiation and/or applying high field stress before irradiation. The resulting defect energy distributions are evaluated after irradiation and/or high field stress via low-frequency noise measurements. Significant increases are observed in acceptor densities for defects with 0.2 and 0.7 eV energy levels. These defects appear to dominate the degradation in threshold voltage and transconductance for these devices. Density functional theory (DFT) calculations show that N vacancy-related defects in GaN and hydrogenated O complexes in AlGaN are strong candidates for the defects with 0.2 eV energy levels in these devices. We also present evidence that the previously unidentified 0.7 eV defect in GaN is a N anti-site defect (N).