Low‐Frequency Noise in AlGaN/GaN High Electron Mobility Transistors Irradiated by γ‐Ray Quanta

Room temperature current–voltage and noise measurements have been made before and after gamma irradiation on AlGaN/GaN high electron mobility transistors (HEMTs) grown on sapphire. The saturation current due to radiation-induced defects shows a nonlinear dependence on radiation dose. The deviation of the device parameters does not exceed 20% at highest radiation dose 109 Rad and the devices with larger gate lengths demonstrate a higher radiation hardness to the 60Co gamma rays. The noise spectra of devices after gamma irradiation follow the flicker noise (1/fγ) dependence with the exponent γ close to one. The Hooge parameter estimated for the HEMTs after gamma irradiation dose does not show a gate-bias dependence and increases by approximately three to five times at radiation dose 2 × 108 Rad. The analysis of noise spectra allowed to identify the major sources of noise generation in the investigated HEMT heterostructures.