Exceptional Repetitive-Short-Circuit Robustness of Vertical GaN Fin-JFET at High Voltage

Abstract

The limited short circuit (SC) capability of GaN high-electron-mobility transistors (HEMTs) has become a critical concern for their adoption in many power applications. Recently, breakthrough SC robustness was demonstrated in a 650-V rated vertical GaN Fin-JFET with a short circuit withstanding time of over 30 μs at 400 V bus voltage (VBUS), showing great potential for automotive powertrain and grid applications. This work presents the first study on the repetitive SC robustness of this GaN Fin-JFET at a VBUS of 400 V and 600 V. The GaN Fin-JFET survived 30,000 cycles of 400 V, 10 μs SC stresses without any degradation in device characteristics. At a 600 V VBUS, it survived over 8,000 cycles of 10 μs SC stresses before an open-circuit failure. This open-circuit failure signature allows the GaN Fin-JFET to retain its avalanche breakdown voltage and is highly desirable for system safety. Besides, an increase in gate leakage was observed during the 600 V repetitive test, which can be used as a precursor to predict device failure. As far as we know, this is the first report of an exceptional repetitive SC robustness in a power transistor at a VBUS close to its rated voltage.