Effect of Gamma Irradiation on DC Performance of Circular-Shaped AlGaN/GaN High Electron Mobility Transistors

The effect of low dose gamma irradiation on DC performance of circular-shaped AlGaN/GaN high electron mobility transistors weas investigated. The drain saturation current (I-DS) increased 11.44% after irradiation with a dose of 700 Gy. Sheet resistance (Rs) was measured from transfer line method and it decreased 3.6% after irradiation. By extracting the resistance between source and drain in the drain I-V curve and combining with TLM data, mobility was found to increase 34.53% after irradiation. The mobility increase may come from the donor-type defects or the strain relaxation effect. Gate lag measurement was also performed and 5% current dispersion was found after irradiation with the dose of 700 Gy, indicating there were more defects generated after irradiation.