Fermi level pinning mitigation in GaN Schottky contacts via UV/O3-treated interfaces

Abstract

GaN has recently emerged as a prominent material for power electronics due to its wide bandgap properties. However, challenges related to interface states at metal/GaN junction cause deviations in device characteristics such as leakage current and breakdown voltage. The interface defects induce Fermi level pinning (FLP) at the metal–GaN interface and significantly affect the electrical performance of devices. In this study, we investigated the impact of ultraviolet/ozone (UV/O₃) treatment on the interface characteristics of metal/GaN junctions, by mitigating FLP phenomenon. The electrical properties of the samples were analyzed after applying UV/O₃ treatment to the GaN surface, followed by the separate deposition of Pt and Ni. Through I–V and C–V curves analysis, we observed a reduction in leakage current along with changes in breakdown voltages and Schottky barrier heights. Our findings demonstrate that the oxide layer formed through the UV/O₃ treatment enhances the interface passivation, reducing defect states and improving device performance. This work provides insights into controlling the properties at the metal–GaN interfaces and elucidating the mechanism of mitigating FLP.