Defects associated with the accommodation of misfit between crystals

A substantial fraction of the defects in epitaxial thin films are formed to accommodate part of the misfit between the stress−free lattice parameters of film and substrate. This paper describes some of the complete dislocations, partial dislocations, and cracks that are made for this purpose. Also described are the optimum division of misfit between dislocations and elastic strain, and the modification of this division caused by the Peierls stress and the barrier to nucleation of dislocation half−loops. The use of misfit strain to remove dislocations, the effect of misfit strain on the mode of film growth, and the evidence for dislocation sources in epitaxial layers are discussed in brief.