Improved Vertical β-Ga₂O₃ Schottky Barrier Diodes With Conductivity-Modulated p-NiO Junction Termination Extension

In this work, we demonstrate a novel conductivity-controlled junction termination extension (JTE) technique using p-type NiO—a key element for the potential commercialization of Ga2O3 power devices. The surface electric field at the Schottky edge is effectively suppressed by the p-type NiO JTE. Simultaneously, it can control the concentration of p-type NiO to maximize the breakdown voltage ( <tex-math notation="LaTeX">Vbr </tex-math> ) by changing the gas atmosphere during magnetron sputtering growth. The electrical characteristics of the <tex-math notation="LaTeX">β </tex-math> -Ga2O3 Schottky barrier diodes (SBDs) with p-type NiO JTE are studied systematically. All <tex-math notation="LaTeX">β </tex-math> -Ga2O3 SBDs with JTE show great advantages in terms of device performance parameters whether at room temperature or high temperature, which indicates the effectiveness of p-NiO JTE in reducing the fringe electric field. In particular, the <tex-math notation="LaTeX">β </tex-math> -Ga2O3 SBDs with an optimized hole concentration of approximately <tex-math notation="LaTeX">10^17 </tex-math> cm <tex-math notation="LaTeX">^-3 </tex-math> for NiO in the JTE region exhibit a low specific ON-resistance of 2.9 <tex-math notation="LaTeX">mΩ </tex-math> cm2 and a high <tex-math notation="LaTeX">Vbr </tex-math> of 2.11 kV, yielding a high power figure-of-merit (PFOM) of 1.54 GW/cm2. Our results demonstrate the great potential of p-NiO as a controllable and reliable technique for junction engineering in <tex-math notation="LaTeX">β </tex-math> -Ga2O3 power devices.