Design of a β-Ga2O3 Schottky Barrier Diode With p-Type III-Nitride Guard Ring for Enhanced Breakdown

This work presents the electrostatic analysis of a novelGa(2)O(3) vertical Schottky diode with three different guard ring (GR) configurations to reduce the peak electric field at the metal edges. Highly doped p-type GaN, p-type nonpolar AlGaN, and polarization-doped graded p-AlGaN are simulated and analyzed as the GR material, which forms a heterojunctionwith theGa(2)O(3) drift layer. GRwith nonpolar graded p-AlGaN with a bandgap larger than Ga2O3 is found to showthe best performance in terms of screening the electric field at themetal edges. The proposedGR configuration is also comparedwith a reportedGa(2)O(3) Schottky diodewith no GR and a structure with high-resistive nitrogen- doped GR. The optimized design is predicted to have a breakdown voltage as high as 6.2 kV and a specific ON-resistance of 3.55 m Omega-cm(2), which leads to an excellent power figure of merit of 10.8 GW/cm(2).