Seeded sublimation growth of 6H and 4H–SiC crystals

Growth of 6H and 4H-SiC crystals via sublimation technique has been studied in a temperature range of 2300–2450°C. The growth rate strongly depends on temperature distribution, growth pressure, and source to seed distance. The influence of the seed quality on the polytype stability and defect occurrence has been studied. 6H–SiC crystals up to 35 mm in diameter and 20 mm in length have been grown with low micropipe density, 50 cm−2. Micropipe free areas up to 1 cm2 have been obtained under optimized growth conditions. The analysis of the results obtained with 4H–SiC growth has shown that this polytype has more narrow window of growth parameters which requires more strict control especially at the initial stage of growth. The seed quality plays an important role for the stability of the polytype and for defect control in the growing crystal.