Effect of heavy ion irradiation on the interface traps of AlGaN/GaN high electron mobility transistors

AlGaN/GaN high electron mobility transistors (HEMTs) were irradiated with heavy ions at various fluences. After irradiation by 2.1 GeV¹⁸¹ Ta³²⁺ ions, the electrical characteristics of the devices significantly decreased. The threshold voltage shifted positively by approximately 25% and the saturation currents decreased by approximately 14%. Defects were induced in the band gap and the interface between the gate and barrier acted as tunneling sites, which increased the gate current tunneling probability. According to the pulsed output characteristics, the amount of current collapse significantly increased and more surface state traps were introduced after heavy ion irradiation. The time constants of the induced surface traps were mainly less than 10 μs.