Observation of Reverse Leakage Currentin(001)β-Gallium Oxide Schottky Barrier Diodesby High Sensitive Emission Microscope

摘要

β-Gallium oxide (β-Ga_2O_3) possesses a wide bandgap of 4.8 eV which makes this material more preferable for high-power electronic devices. Besides, large size single crystal of β-Ga_2O_3 can be achieved from melt growth techniques that are economically beneficial for large-scale device fabrication. However, crystal defects in this material are the main obstacle for the reliability of device operation, yet their impact on device characteristic is not clearly known. Therefore, in this study, by utilizing a high sensitive emission microscope, we investigate and identify the origin of reverse leakage current in β-Ga_2O_3 Schottky barrier diodes (SBDs).Vertical-type EFG-grown (001) β-Ga_2O_3 SBDswere fabricated and investigated. Ni/Au was evaporated on the surface to form Schottky barrier contacts, and Ti/Au was evaporated on the back face to form ohmic contact. SBDs were observed from the back face by the emission microscope with a high sensitive CCD camera during reverse bias operation. After the emission microscope observation, the Schottky contacts and the surface were etched to form etch pits and patterns.