Heavy-Ion Radiation Effects in AlGaN/GaN High-Electron-Mobility Transistors

Heavy-ion radiation tolerance of wide-bandgap gallium nitride (GaN) high-electron-mobility transistors (HEMTs) has been studied as a function of bias voltage, ion linear energy transfer (LET), radiation flux, and total fluence. A statistically significant number of heavy-ion-induced gate dielectric breakdowns were observed, including both soft breakdown (SBD) and hard breakdown (HBD) events. Specific fluence-to-failure experiments and constant-fluence experiments were used to explore the gate dielectric degradation mechanism. Our data provide evidence that radiation-induced breakdown is associated with defect-related conduction paths formed across the dielectric in response to radiation-induced charge injection.