Design of a $\beta$-Ga$_2$O$_3$ Schottky Barrier Diode With p-type III-Nitride Guard Ring for Enhanced Breakdown

TL;DR

This paper introduces a novel Ga$_2$O$_3$ Schottky diode with a p-type III-Nitride guard ring, significantly improving breakdown voltage and electric field management for power applications.

Contribution

It proposes and analyzes a new heterojunction guard ring design using p-type III-Nitride materials to enhance breakdown voltage and electric field distribution in Ga$_2$O$_3$ Schottky diodes.

Findings

Guard ring with non-polar graded p-AlGaN shows best electric field screening.

Optimized diode design achieves breakdown voltage of 5.3 kV.

Power figure of merit reaches 7.91 GW/cm$^2$.

Abstract

This work presents the electrostatic analysis of a novel Ga$_2$O$_3$ vertical Schottky diode with three different guard ring 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 guard ring material, which forms a heterojunction with the Ga$_2$O$_3$ drift layer. Guard ring with non-polar graded p-AlGaN with a bandgap larger than Ga$_2$O$_3$ is found to show the best performance in terms of screening the electric field at the metal edges. The proposed guard ring configuration is also compared with a reported Ga$_2$O$_3$ Schottky diode with no guard ring and a structure with a high resistive Nitrogen-doped guard ring. The optimized design is predicted to have breakdown voltage as high as 5.3 kV and a specific on-resistance of 3.55 m$\Omega$-cm$^2$ which leads to an excellent power figure of merit of 7.91 GW/cm$^2$.