Vertical GaN Power Transistor With Intrinsic Reverse Conduction and Low Gate Charge for High-Performance Power Conversion

In this paper, a novel vertical normally-off GaN power transistor featuring a split gate with the intrinsic reverse conduction (RCVFET) and low gate charge is proposed. The static and dynamic device characteristics are studied and analyzed by simulation with Sentaurus TCAD. Benefiting from the monolithically integrated freewheeling diode, the RCVFET characteristics of the device are independent with the threshold voltage VTH, while a low reverse turn-on voltage VR,ON of 0.8 V is obtained. The RCVFET exhibits a short reverse recovery time Trr of 13 ns and low reverse recovery charge Qrr of 47 nC. Due to the split-gate design, the gate charge of the RCVFET is also significantly reduced, favoring the improved switching speed and lower switching power loss. QGD is as low as 80 nC which is only 20% of that in the reference device without splitgate design. Accordingly, the turn-off transient time and power dissipation of the RCVFET are reduced by 45% and 55.7%, respectively. Meanwhile, the device exhibits a low on-resistance RON of 0.98 mQ · cm2 and a high breakdown voltage (BV) of 1.8 kV.