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 (HEMT) has been studied as a function of bias voltage, ion 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.