In-situ observation of silicon carbide sublimation growth by X-ray topography

The crystal growth of silicon carbide (SiC) was studied by ira-situ observa tion using X-ray topographic technique. The growth was performed by a subli mation method (the modified Lely method). The generation and evolution of d efects and dislocations were observed as topographs in a real-time display. Defects and dislocations analyzed by the in-situ technique were compared w ith the postprocess observations using optical microscopy and X-ray topogra phy. Dislocations in the initial growth layer and typical large defects, su ch as micropipes, macrodefects and domain boundaries, were investigated, We showed the possibility that large defects are induced by the accumulation of dislocations in the initial growth layer. Moreover, we observed that inh omogeneous growth starting in parts on the seed surface during the initial growth results in new defects in the growing crystal. We discuss the import ance of dislocation and nucleation control on the SiC seed crystal during t he initial growth, on the basis of facts and findings obtained by the in-si tu as well as postprocess observations. (C) 2001 Published by Elsevier Scie nce B.V.