Radiation-Induced Defect Evolution and Electrical Degradation of AlGaN/GaN High-Electron-Mobility Transistors

Threshold-voltage shifts and increases in 1/fnoise are observed in proton-irradiated AlGaN/GaN high-electron-mobility transistors, indicating defect-mediated device degradation. Quantum mechanical calculations demonstrate that low-energy recoils caused by particle interactions with defect complexes are more likely to occur than atomic displacements in a defect-free region of the crystal. We identify the responsible defects and their precursors in the defect-mediated displacement mechanism. The electronic properties of these defects are consistent with the increases in threshold voltage and 1/fnoise in proton irradiation experiments.