Study of leakage current in GaN junction field-effect transistor under heavy ion radiation

Abstract

GaN junction field-effect transistors (JFETs) were fabricated and subjected to 333.7 MeV gold (Au) ion irradiation to investigate the effects of swift heavy ions on device performance. Electrical characterization following irradiation revealed a significant and permanent increase in off-state leakage current. The leakage was attributed to a vertical conduction mechanism, likely to originate from latent ion tracks formed within the device during SHI exposure. The results indicate a latent track-induced vertical leakage path in GaN JFETs under SHI irradiation. Temperature-dependent current–voltage measurements indicated a voltage-dependent activation energy, suggesting a field-assisted transport process. Device simulations reproduced the experimental leakage behavior and identified the critical leakage path at the p+-GaN/p-GaN region, where the local electric field is most intense. The conduction mechanism was found to be consistent with the Poole–Frenkel emission model, from which a barrier height of approximately 0.38 eV was extracted. These findings offer insights into SHI-induced degradation in GaN devices and provide guidance for designing radiation-hardened GaN electronics for space applications.