It was argued that micro-pipes in SiC crystals grown by the physical vapor transport process form independently of screw dislocations. A mechanism involving liquid droplets of Si containing some C or graphite particles was proposed to explain the formation of micro-pipes. The observed strain fields associated with micro-pipes were attributed to the presence of screw dislocations in their vicinity. An expression was developed that relates the change in radius of a micro-pipe to the number of screw dislocations that were eliminated during its expansion.

Origins of Micropipes in SiC Crystals. S.Mahajan: Applied Physics Letters, 2002, 80[23], 4321-3