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

Abstract

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 $V_{\mathrm {TH}}$ , while a low reverse turn-on voltage $V_{R,\mathrm{\scriptscriptstyle ON}}$ of 0.8 V is obtained. The RCVFET exhibits a short reverse recovery time $T_{\mathrm {rr}}$ of 13 ns and low reverse recovery charge $Q_{\mathrm {rr}}$ 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. $Q_{\mathrm {GD}}$ is as low as 80 nC which is only 20% of that in the reference device without split-gate 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 $R_{\mathrm{\scriptscriptstyle ON}}$ of 0.98 $\text{m}\Omega \cdot \text {cm}^{\mathbf {2}}$ and a high breakdown voltage (BV) of 1.8 kV.