Probe-induced surface defects: Origin of leakage current in halide vapor-phase epitaxial (001) β-Ga2O3 Schottky barrier diodes
Sayleap Sdoeung, Kohei Sasaki, Katsumi Kawasaki, Jun Hirabayashi, Akito Kuramata, Makoto Kasu
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.