Influence of heavy ion irradiation on DC and gate-lag performance of AlGaN/GaN HEMTs

AlGaN/GaN high electron mobility transistors (HEMTs) were irradiated by 256 MeV ¹²⁷I ions with a fluence up to 1× 10¹⁰ ions/cm² at the HI-13 heavy ion accelerator of the China Institute of Atomic Energy. Both the drain current I_d and the gate current I_g increased in off-state during irradiation. Post-irradiation measurement results show that the device output, transfer, and gate characteristics changed significantly. The saturation drain current, reverse gate leakage current, and the gate-lag all increased dramatically. By photo emission microscopy, electroluminescence hot spots were found in the gate area. All of the parameters were retested after one day and after one week, and no obvious annealing effect was observed under a temperature of 300 K. Further analysis demonstrates that swift heavy ions produced latent tracks along the ion trajectories through the hetero-junction. Radiation-induced defects in the latent tracks decreased the charges in the two-dimensional electron gas and reduced the carrier mobility, degrading device performance.