Observation of comet-shaped defect as killer defect in halide vapor phase epitaxial (001) -Ga₂O₃ and its impact on Schottky barrier diodes

We observed killer defects that served as reverse leakage current paths for halide vapor phase epitaxial (001) & beta;-Ga2O3 Schottky barrier diodes, which resulted in a leakage current of -0.46 & mu;A at reverse bias of -100 V. Synchrotron X-ray topography revealed comet-shaped contrasts extending along [010] which are induced from the strain field surrounding the defects. They consisted of perfect (100)-cracks and horizontal-oriented (001) cracks. The cross-sectional scanning transmission electron microscopy observation showed (100)-cracks on the surface and dislocations along [100] beneath the surface. This defect was speculated to be generated from damage during the chemical-mechanical polishing.