Overcurrent and Short-circuit Capability Experimental Investigation for GaN HEMT at Cryogenic Temperature

Recent research reveals that gallium nitride (GaN) devices achieve significantly reduced on-state resistance and faster switching speed operating at cryogenic temperature. These characteristics enable GaN-based power converter to achieve higher efficiency and power density and make GaN device an excellent candidate for cryogenic power electronics applications. However, overcurrent and short-circuit capability of GaN device at cryogenic temperature have not been evaluated. This paper characterizes a 650V-30A enhancement-mode GaN high-electron mobility transistor (HEMT) and experimentally evaluated the overcurrent and short-circuit capability at cryogenic temperature. Testing results show that this GaN HEMT achieves >5X conduction loss reduction and 30% switching loss reduction at cryogenic temperature. Moreover, GaN HEMT is capable of operating at around 4X of rated current at cryogenic temperature. The short-circuit capability at cryogenic temperature is similar to that at room temperature. Both the device failure threshold dc voltage and short-circuit withstand time are almost unchanged at cryogenic temperature.