Formation of dislocation superlattices in epitaxial systems

Abstract

The role of lattice misfit, ƒ, of the film and the substrate in epitaxial crystal growth has been reviewed. It has been shown that the most perfect single crystal films can be grown by the Frank-van der Merwe mode both at very small misfit values (ƒ ≈ 0) and at very high ones (ƒ ≳ 0.05). Misfit dislocation networks are formed on the interfaces of heterostructures at ƒ ≳ 0.05 with such a high degree of periodicity that planar dislocation superlattices with a period D = 20–200 Å can be grown. The formation of misfit dislocations at the interfaces of heterostructures and multilayer epitaxial structures can be avoided by covering the substrate surface with submonolayer coatings of impurity atoms, weakening the interface interaction of the epitaxial layer atoms with the substrate.