Suppression of SiC Inclusions in 4H-SiC Crystals Grown from Si–Cr–C-Based Solution Saturated with SiC

The formation of parasitic SiC inclusions was completely suppressed during SiC solution growth using an SiC liner crucible that provided growth conditions saturated only with SiC. In contrast, SiC inclusions formed in solution growth using a graphite crucible as a carbon source. For solution growth using a graphite crucible, the formation frequency of SiC inclusions increased with the Cr content of the solvent, which was ascribed to the increasing C solubility. The dissolution behavior of graphite crucibles containing Si–Cr solvents was investigated; we found that the thickness of the Si–SiC–C composite layer formed on the graphite crucible wall decreased with increasing Cr content of the solvent and disappeared for solvents with a Cr content higher than 40 mol %. This suggested metastable C dissolution directly from the graphite crucible, which may supply excess C beyond the C solubility of the solvents at SiC saturation. Growth experiments and computational fluid dynamics simulations indicated that excess C supply may drive the generation of SiC particles in solution. Use of SiC-saturated conditions is a promising approach to obtain high-quality bulk SiC crystals from solution growth.