Improved Vertical β-Ga<sub>2</sub>O<sub>3</sub> Schottky Barrier Diodes With Conductivity-Modulated p-NiO Junction Termination Extension
Weibing Hao, Feihong Wu, Wenshen Li, Guangwei Xu, Xuan Xie, Kai Zhou, Wei Guo, Xuanze Zhou, Qiming He, Xiaolong Zhao, Shu Yang, Shibing Long
Abstract
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 ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {br}}$ </tex-math></inline-formula> ) by changing the gas atmosphere during magnetron sputtering growth. The electrical characteristics of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga2O3 Schottky barrier diodes (SBDs) with p-type NiO JTE are studied systematically. All <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga2O3 SBDs with an optimized hole concentration of approximately <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{17}}$ </tex-math></inline-formula> cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{3}}$ </tex-math></inline-formula> for NiO in the JTE region exhibit a low specific ON-resistance of 2.9 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}\Omega $ </tex-math></inline-formula> cm2 and a high <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {br}}$ </tex-math></inline-formula> 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga2O3 power devices.