Observation and Suppression of Growth Pits Formed on 4H-SiC Epitaxial Films Grown Using Halide Chemical Vapor Deposition Process

In this study, the origin of growth pits on the surface of 4H-silicon carbide epitaxial films grown using a chemical vapor deposition reactor was clarified by evaluating the surface morphology of substrates immediately before the epitaxial growth and of epitaxial films. When the film was grown under non-optimized conditions, we found that numerous Si particles were formed on the surface of the substrate before the epitaxial growth and that the numerous growth pits on the subsequently grown epitaxial film were originated from Si particles. We observed that, by increasing the HCl flow rate through the outer nozzles in the gas inlet, which has a double-pipe structure consisting of inner and outer nozzles, the growth pit density was successfully decreased.