1.48 MV⋅cmˉ¹/0.2 mΩ⋅cm² GaN Quasi-Vertical Schottky Diode via Oxygen Plasma Termination

Abstract

In this letter, a high-performance GaN quasi-vertical Schottky barrier diode (SBD) is demonstrated via oxygen plasma termination. A specific on-resistance of 0.2 $\text{m}\Omega \cdot $ cm2, turn-on voltage of 0.71 V, and breakdown voltage of 193 V are achieved with a GaN SBD of $1.3~\mu \text{m}$ drift layer. The average breakdown electric field is calculated to be about 1.48 MV/cm, which is much higher than the state-of-art value for GaN vertical SBDs. The temperature-dependent forward and reverse I-V characteristics confirm the high-temperature stability of the oxygen plasma treated SBDs. X-ray spectroscopy and Kelvin Probe Force Microscopy reveal that the surface potential is increased after the oxygen plasma treatment, which results in the suppression of the leakage current and improvement of the breakdown electric field.