Probe-induced surface defects: Origin of leakage current in halide vapor-phase epitaxial (001) β-Ga2O3 Schottky barrier diodes

Abstract

The elimination of killer defects, which are responsible for the reverse leakage current and breakdown at low voltage in β-gallium oxide (β-Ga2O3) Schottky barrier diodes (SBDs), is crucial for the commercialization of the power devices. We found probe-induced surface defects, which act as a reverse leakage current path in β-Ga2O3 SBDs. Each defect corresponds to a reverse leakage current of −0.725 μA at a reverse bias of −140 V. These defects are wrinkle shaped, which consists of a pair of the convex and concave structures, as observed by atomic force microscopy. The residual strain around the defects was observed as bright contrasts in the x-ray topography image. The surface defect comprised an 83 nm high convex and a 26 nm deep concave structure. A probe attachment at the pressure of 0.206 GPa induced the surface defect along with a reverse leakage current of −3.75 nA at a reverse voltage of −140 V.