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

The effect of 5 MeV proton irradiation on DC performance and reliability of circular-shaped AlGaN/GaN high electron mobility transistors were investigated. The drain saturation current (I-DSS) reduced 12.5% and the sheet resistance increased 9.2% after irradiation with a dose of 2x10(14) 1/cm(2). Threshold voltage shifted more positively with a dose of 2x10(14) 1/cm(2) compared to 2x10(13)/cm(2). Besides, the breakdown voltage improved 39.8% after irradiation with dose of 2x10(14) 1/cm(2). Simulation was done and the peak electric field at the drain side of the gate edge was found to be reduced after irradiation. The defects generated after irradiation at the AlGaN/GaN interface create a virtual gate and thus reduce the electric field. Gate lag measurement was performed to characterize the defects. The current dispersion of DC to high frequency indicates the defects had been generated after irradiation, which is in agreement with the simulation data.