Design of a 10 kV and 16.5 GW cm⁻² NiO/β-Ga₂O₃ Heterojunction Diode on a Complete Wafer with a Positive Beveled-Mesa

In this paper, a p-NiO/n-Ga2O3 heterojunction diode with positive bevel angle termination based on a complete wafer is proposed, verified and optimized by TCAD. The results indicated the optimal angle of 78° for the positive bevel angle terminal, which reduces the peak surface electric field to 6 MV cm−1 and effectively avoids the premature breakdown of the terminal of the Ga2O3 layer. Further, the effect of each dielectric passivation on the terminal electric field was investigated, where SiO2 was determined to be the optimal passivation material to minimize the peak electric field on the side of the terminal. Ultimately, considering the effect of drift layer thickness on breakdown voltage (BV) and specific on-resistance (Ron·sp), the diode achieves BV up to 10 kV and optimal power figure of merit (PFOM) over 16.5 GW cm−2 when the drift layer thickness is 20 μm, which fully demonstrates the great potential of positively beveled terminal-optimized p-NiO/n-Ga2O3 heterojunction diodes for next-generation high-voltage and high-power applications.