IMPROVEMENT IN THE GROWTH-RATE OF CUBIC SILICON-CARBIDE BULK SINGLE-CRYSTALS GROWN BY THE SUBLIMATION METHOD

Silicon carbide (SIG) is a valuable electronic material for high-tempe rature and high-power applications. The two most studied forms of SiC are the 6H and jC-SiC polytypes. Cubic SiC is attractive because of th e high low field mobility and the zincblende crystal structure. Presen tly, 3C-SiC is usually produced using chemical vapor deposition CVD te chniques on silicon substrates. Because of a large lattice mismatch (s imilar to 20%), the quality of the CVD films is low, and therefore, se veral investigators have tried to produce bulk 3C-SiC using sublimatio n technology. We have investigated the growth of 3C-SiC in close space environment. Utilizing this geometry, we have been able to obtain gro wth rates in excess of 251 mu m/h by optimizing source powder height, temperature gradient, seed temperature and system pressure. The seed c rystals utilized for this study were off-axis (1 0 0) 3C-SiC films gro wn on Si substrates (substrates removed prior to growth). On these sub strates a clear yellow 3C-SiC material was grown. Etch results indicat e a lower density of stacking faults (by at least three orders of magn itude) for the bulk crystals. Additionally, second generation growths using sublimation bulk crystals as substrate material were investigate d.