Study on irradiation effect and damage mechanism in cascode GaN HEMT irradiated by 10 MeV electron

Abstract

This study investigated the irradiation effect of cascode-structure GaN HEMT (High Electron Mobility Transistor) devices, employing high-energy electrons with an energy of 10 MeV and irradiation doses ranging from 5 to 80 Mrad(Si). The variation of electrical properties of the device under annealing condition was analyzed. Geant4 and TCAD simulations were used to analyze the irradiation effect and damage mechanisms. The results show that the threshold voltage has obvious negative drift and the drain current increases after irradiation. The threshold voltage deviation amplitude of the device increases with the increase of irradiation dose, and the maximum deviation is 1.41V. Annealing at high temperatures (80 °C, 120 °C and 145 °C) partially restores the electrical properties, with a 0.49 V restoration in threshold voltage at 145 °C. Geant4 simulations reveal that enhanced Si MOSFET is more susceptible to total dose effects. TCAD simulations of enhanced Si MOSFET devices demonstrate an increase in electric field intensity, trapped electron concentration, and hole concentration in Si and SiO₂ layers with the increase of irradiation dose. These findings can provide support for the space application and irradiation hardening of cascode GaN HEMT devices.