Polytype stability in seeded sublimation growth of 4H-SiC boules

Process conditions for stable single polytype growth of 4H-SiC boules via a seeded sublimation technique have been developed. Reproducible results can be obtained in a narrow temperature interval around 2350 degrees C and on the C-face of 4H-SiC seeds. Evidence is presented that during the initial s tage of growth, morphological instabilities may occur resulting in structur al defects. A solution is proposed based on the experimental findings, i.e. the first regions of growth ought to be carried out at a low supersaturati on (growth rate similar to 100 mu m/h) until a proper growth front has deve loped. (C) 2000 Elsevier Science B.V. All rights reserved.