Dislocation bends in a film/substrate heterostructure

Threading dislocations in thin-film/substrate heterostructures interact elastically with the free surface. In the case of a plastically relaxed heterostructure Si0.68Ge0.32/Si(0 0 1), and thanks to a new contrast simulation programme, it is shown that the short skew emerging legs of the threading dislocations are of screw character, which explains the easy production of 60° interfacial dislocations by multiple cross-slips of the emerging legs.