Several characteristic features of surface-damage-related threading dislocations in SiC epitaxial layers have been investigated by transmission electron microscopy. Most of the observed threading dislocations are perfect-edge type with line direction along [0001] and Burgers vector of a/3(11-20). The edge dislocations are arranged in form of cellular structures with cell walls aligned preferentially along (1-100) directions. Some small isolated cells were also observed in the areas of lower dislocation density. The density of elementary screw dislocations in the overgrowth was approximately 10(5) cm(-2) and is about two orders of magnitude lower than the edge dislocation density. The screw dislocations appeared in pairs with the opposite sign of Burgers vectors separated by about 0.3 mum. The formation of threading dislocations is associated with the subsurface damages caused by plastic deformation during the mechanical polishing process. (C) 2003 The Electrochemical Society.