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 (
${V}_{\text {br}}$
) by changing the gas atmosphere during magnetron sputtering growth. The electrical characteristics of the
$\beta $
-Ga2O3 Schottky barrier diodes (SBDs) with p-type NiO JTE are studied systematically. All
$\beta $
-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
$\beta $
-Ga2O3 SBDs with an optimized hole concentration of approximately
$10^{{17}}$
cm
$^{-{3}}$
for NiO in the JTE region exhibit a low specific ON-resistance of 2.9
$\text{m}\Omega $
cm2 and a high
${V}_{\text {br}}$
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
$\beta $
-Ga2O3 power devices.