Physical Vapor Transport Growth of 4H-SiC on {000-1} Vicinal Surfaces

Bulk 4H-SiC crystals were grown on 4° off-axis seeds by the physical vapor transport technique. Two completely different surface morphologies of as-grown crystals were observed by laser scanning confocal microscopy. The formation mechanisms of the different surface morphologies are proposed and discussed. We found that the facet formation and migration on the 4° off-axis seeds largely depended on the profile evolution of the temperature field in the growth cell over a long-term growth run. At the interface between the two growth regimes, some grown-in defects, including micropipes, dislocations and polytype inclusions, were frequently observed by polarizing optical microscopy and chemical etching. The stress induced by step coalescence could be responsible for the formation of these grown-in defects.