Improved β-Ga2O3 Schottky Barrier Diodes Featuring p-NiO Gradual Junction Termination Extension within Mesa Structure

In this work, we designed and fabricated high performance $\beta-\text{Ga}_{2}\mathrm{o}_{3}$ Schottky barrier diodes (SBDs) with composite termination that combines mesa and gradual junction termination extension (MJTE). The mesa avoids the peak electric field (E-field) at the anode periphery, while the design of gradual multilayer NiO effectively modulates the gradient of E-field distribution. Systematic TCAD simulations were conducted to study the relationship between E-field distribution with NiO thickness, mesa depth, and JTE length. Combined with the optimized parameters, the breakdown voltage of the device increased from 738 V to 2116 V, resulting in a seven-fold improvement in power figure-of-merit (PFOM) (from 81.05 MW/cm² to 608.35 MW/cm2). This work provides a practical and effective solution for enhancing the performance of $\beta-\text{Ga}_{2}\mathrm{O}_{3}$ SBDs.