Reverse Current Stress Induced Dynamic Ron of GaN HEMTs in Soft-Switching Mode

The utilization of gallium nitride (GaN) in power electronics has been validated for mass production through its successful implementation in power charger applications. Eliminating technical roadblocks is crucial for the widespread adoption of GaN, and one such roadblock is the dynamic ON-resistance (Ron) effect that can lead to energy losses and reliability issues. While this effect has been improved in successive generations of commercial GaN devices, this letter argues that it still warrants attention at present. In particular, in soft-switching half-bridge circuits, certain operations can induce the dynamic Ron effect on devices that behaves well in hard-switching circuits. In our test conditions, the dynamic Ron effect is more likely to occur under high reverse current stress in soft switching mode. We believe that the dynamic Roneffect in the device is related to the presence of traps in the GaN buffer, and we use TCAD simulation to explain this phenomenon. Our findings and postulations regarding the root cause of the problem could aid in the optimization of GaN power devices.