Gate dielectric layer mitigated device degradation of AlGaN/GaN-based devices under proton irradiation

In this study, the simulations of AlGaN/GaN-based devices, including AlGaN/GaN high electron mobility transistor (HEMT), Al2O3 metal-oxide-semiconductor high electron mobility transistor (MOSHEMT), and SiNx metal-insulator-semiconductor high electron mobility transistor (MISHEMT), were studied to investigate the degradation mechanism after proton irradiation. The vacancies produced by proton irradiation, especially Ga vacancy (VGa), are found to be responsible for the device degradation by carrier removal and mobility degradation, which directly influence the saturation drain current and maximum transconductance of AlGaN/GaN-based devices. Furthermore, AlGaN/GaN HEMTs with gate dielectrics (Al2O3, SiNx) exhibit better irradiation resistance than traditional AlGaN/GaN HEMTs, which produce fewer vacancies at the channel after proton irradiation. Al2O3 MOSHEMTs also show better performance than SiNx MISHEMTs in resisting proton damage. Therefore, a high-quality dielectric layer is a key factor to improve the reliability of AlGaN/GaN-based devices after proton irradiation.