Effect of low dose γ-irradiation on DC performance of circular nnlGaN/GaN high electron mobility transistors

The changes in direct current performance of circular-shaped AlGaN/GaN high electron mobility transistors (HEMTs) after Co-60 gamma-irradiation doses of 50, 300, 450, or 700 Gy were measured. The main effects on the HEMTs after irradiation were increases of both drain current and electron mobility. Compton electrons induced from the absorption of the gamma-rays appear to generate donor type defects. Drain current dispersions of similar to 5% were observed during gate lag measurements due to the formation of a virtual gate between the gate and drain resulting from the defects generated during gamma-irradiation. (C) 2014 American Vacuum Society.