Heavy Ion-Induced Permanent Damage in Cascode Power GaN HEMTs

Heavy ion-induced leakage current increase is reported for a cascode gallium nitride (GaN) high-electron-mobility-transistor (HEMT), which is related to the damage between the gate and the drain of the embedded depletion-mode (DM) GaN HEMT. The local high temperature-induced damage near the drain contact may be directly related to the leakage degradation. The influences of drain bias and temperature on the leakage increase degradation are investigated by irradiation experiments and technology computer aided design (TCAD) simulations. Radiation-induced gate rupture is also observed for the cascode GaN HEMT during Bi ion irradiation with a high linear energy transfer (LET) value. Although the DM GaN HEMT is the most sensitive component to heavy ion irradiation in the cascode GaN HEMT system, there is also a risk of failure for the Si MOSFET component.