Band alignment of SnO/β-Ga2O3 heterojunction and its electrical properties for power device application

Abstract In this study, we present the fabrication of vertical SnO/ β -Ga 2 O 3 heterojunction diode (HJD) via radio frequency (RF) reactive magnetron sputtering. The valence and conduction band offsets between β -Ga 2 O 3 and SnO are determined to be 2.65 and 0.75 eV, respectively, through X-ray photoelectron spectroscopy, showing a type-Ⅱ band alignment. Compared to its Schottky barrier diode (SBD) counterpart, the HJD presents a comparable specific ON-resistances ( R on,sp ) of 2.8 mΩ·cm² and lower reverse leakage current ( I R ), leading to an enhanced reverse blocking characteristics with breakdown voltage (BV) of 1675 V and power figure of merit (PFOM) of 1.0 GW/cm². This demonstrates the high quality of the SnO/ β -Ga 2 O 3 heterojunction interface. Silvaco TCAD simulation further reveals that electric field crowding at the edge of anode for the SBD was greatly depressed by the introduction of SnO film, revealing the potential application of SnO/ β -Ga 2 O 3 heterojunction in the future β -Ga 2 O 3 -based power devices.