Effect of Heavy Ion Radiation on Electrical Performance of AlGaN/GaN HEMTs in Non-Gate Region

Abstract

This study employs different types and energies of heavy ions to irradiate AlGaN/GaN high electron mobility transistors (HEMTs), inducing defects with a non-uniform depth distribution in the GaN epitaxial layer beneath the non-gate region. By integrating experimental and simulation approaches, we investigate the variation patterns of the device’s electrical performance as a function of irradiation fluence. Through electrical performance testing and simulations using extreme-environment radiation effect technology computer aided design (ERETCAD) software, it was observed that heavy ion-induced damage is confined to the GaN epitaxial layer beneath the non-gate region, the saturated drain current ( ${I} _{\mathbf {ds}}$ ) decreases with increasing irradiation fluence, and the threshold voltage ( ${V} _{\mathbf {th}}$ ) of the device remains unchanged. Heavy ion radiation introduces displacement defects in the GaN layer, and as the distance from the 2-D electron gas (2DEG) increases, the Coulomb scattering effect of these defects on carriers diminishes. Consequently, by accounting for the scattering effects of radiation-induced charged defects on carriers, the traditional non-ionizing energy loss (NIEL) value is refined. This adjustment leads to an equivalent degradation phenomenon where the ${I} _{\mathbf {ds}}$ under different heavy ion irradiations correlates with the total effective non-ionizing energy deposition (TNID ${}_{\mathbf {effective}}$ ).