Evaluation and reduction of epitaxial wafer defects resulting from carbon-inclusion defects in 4H-SiC substrate

In this study, we investigated the epitaxial surface defects resulting from the carbon-inclusion defects in 4H-SiC substrates. Most carbon-inclusion defects developed into one of three types of epitaxial surface defects under normal epitaxial growth conditions. Among them, we found a regular hexagonal pit by high-resolution microscopy, which we regarded as a large-pit defect, and which had an adverse impact on the reverse electrical characteristics of Schottky barrier diodes. Conversion of a carbon-inclusion defect to a large-pit defect or a triangular defect could be reduced by reducing the C/Si ratio.