Temperature Dependent Electrical Characteristics of Neutron Irradiated AlGaN/GaN HFETs

Low temperature neutron irradiated Al_0.27Ga_0.73N/GaN heterostructures reveal a complex temperature dependent displacement damage formation process. This process results in differences in drain currents at low (80 K) versus high (294 K) temperatures. Irradiation increases the gate and drain currents at 80 K, and decreases the drain current at room temperature. These effects saturate at ~ 3 times 10¹⁰ n/cm² indicating complexing with a native impurity. After a room temperature anneal, the effect on the gate current persists and the drain current partially recovers. A two-step persistent interface trap formation model is presented that explains these results. This model is further supported by CV measurements at 80 K and 294 K after annealing.