Fig. 1. Diagram of P-GaN enhanced AlGaN/GaN HEMT device(a) Two-dimensional structure, (b) Front of physical picture, (c) Back of physical picture

Fig. 2. Flow chart of γ-ray irradiation experiment (a) and experiment equipment layout diagram (b)

Fig. 3. Transfer characteristics (a) and output characteristics (b) of the enhanced AlGaN/GaN HEMT devices before and after irradiation under GND-state bias

Fig. 4. Transfer characteristic of the device before and after γ-ray irradiation with 1.0 Mrad(Si) under two bias conditions(a) OFF-state bias, (b) ON-state bias

Fig. 5. Output characteristic of the device before and after γ-ray irradiation with 1.0 Mrad(Si) under two bias conditions(a) OFF-state bias, (b) ON-state bias

Fig. 6. Gate leakage current characteristics of the device before and after 1.0 Mrad(Si) γ-ray irradiation under two bias conditions(a) OFF-state bias, (b) ON-state bias

Fig. 7. The variation of AlGaN/GaN HEMT devices characteristics changes with irradiation dose, annealing time and annealing temperature (a) Maximum transconductance, (b) Saturation drain current

Fig. 8. (a) Energy band diagram of P-gate enhanced AlGaN/GaN HEMT devices and (b) the electrical properties of defects in GaN systems depend on the location diagram of Fermi levels^[18]

Fig. 9. Charge distribution diagram of AlGaN/GaN HEMT device before and after electrical stress^[24](a) Before electrical stress, (b) After electrical stress