A Novel Trench-Gated Vertical GaN Transistor With Dual-Current-Aperture by Electric-Field Engineering for High Breakdown Voltage

In this work, a novel trench-gated CAVET featuring a p-GaN island for breakdown voltage improvement is proposed. The p-GaN island inserted between the two p-GaN current-blocking-layer (CBL) constructs a dual-current-aperture vertical transistor (DCAVET), which enables to engineer the electric-field (E-field) distribution in the buried p–n-junction for voltage sustaining. The device operation mechanism and characteristics were investigated by TCAD simulation. By delicately designing the device structural parameters and optimizing the doping concentration, the premature punchthrough and high ${E}$ -field induced avalanche breakdown were effectively suppressed at even higher reverse blocking voltage. The proposed DCAVET achieves excellent balance between punchthrough and avalanche breakdown, delivering a high breakdown voltage of 1504 V and low ${R}_{\text {on,sp}}$ of 0.77 $\text{m}\Omega \cdot $ cm². The trench gate DCAVET demonstrates a flexible approach to engineer the ${E}$ -field distribution to achieve kilo-volts GaN power transistors.