Materials Science Forum, Vol.483, 21-24, 2005
A study of 6H-seeded 4H-SIC bulk growth by PVT
4H-SiC crystals were grown using the seeded sublimation technique (modified Lely technique) in the temperature range of 1950-2200° C. The nucleation of 4H-SiC on 6H-SiC has been optimized and 4H-SiC crystals of 1cm thickness were grown using 6H-SiC seeds. a-face and c-face wafers obtained from the grown boules were characterized by KOH etching, X-ray diffraction, and Raman scattering studies. Complete polytypic homogeneity of 4H SiC was obtained during growth and it was found that the 6H to 4H transition occurs in three ways: 1) without a transition layer, 2) with thick 6H-SiC layer growth, and 3) with traces of 3C SiC inclusions. The crown regions of the grown crystals exhibit an X-ray rocking curve width of 21 arcsecs.
Keywords:4H-SiC;6H-SiC;polytypic transition;crystal growth;x-ray rocking curve;KOH etching;modified lely technique;PVT