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

The crystal growth of silicon carbide (SiC) was studied by in-situ observation using X-ray topographic technique. The growth was performed by a sublimation method (the modified Lely method). The generation and evolution of defects and dislocations were observed as topographs in a real-time display. Defects and dislocations analyzed by the in-situ technique were compared with the postprocess observations using optical microscopy and X-ray topography. Dislocations in the initial growth layer and typical large defects, such 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 inhomogeneous growth starting in parts on the seed surface during the initial growth results in new defects in the growing crystal. We discuss the importance of dislocation and nucleation control on the SiC seed crystal during the initial growth, on the basis of facts and findings obtained by the in-situ as well as postprocess observations.