Screw dislocation, threading edge dislocation and basal plane dislocation in 4H-SiC substrates and epitaxial layers were observed by X-ray topography using synchrotron radiation. Distribution of basal plane dislocation is markedly different between substrates and epitaxial layers. Basal plane dislocations in the substrate are are-shaped and show no distribution direction. Conversely, those in the epitaxial layer are straight and directed towards the off-orientation. The propagation of dislocations from the substrate to the epitaxial layer can be directly observed. Threading edge dislocations in the substrate are propagated as threading edge dislocations into the epitaxial layer. Basal plane dislocations in the substrate are mostly deflected to threading edge dislocations, and the rest. are propagated as basal plane dislocations in the epitaxial layer. (C) 2003 Elsevier B.V. All rights reserved.