10 kV GaN-on-GaN PN power diode with double field plate structure

GaN-based power devices have great potential for medium-to-high voltage applications. In this work, we present the device design of a vertical GaN-on-GaN PN power diode using a double field plate structure and guard-rings for electrical field management to achieve a 10 kV breakdown voltage. Simulations show that this device design with a 75 μm thick drift layer and a doping density of 1 × 1015 cm−3 has a breakdown voltage of 10.5 kV and ∼90.5% electrical field management efficiency. Experimentally, the fabricated diode with a ∼74 μm thick drift layer and Nd–Na concentration of 1 × 1015 cm−3 demonstrates a breakdown voltage of 10.3 kV on a bulk GaN substrate. The device has an on-resistance of 8 mΩ cm2 and a Baliga figure of merit of 13.3 GW/cm2. Compared to the theoretical breakdown voltage of this device design, the fabricated device has an overall breakdown efficiency of 89%.