Epitaxial deposits which consisted of a substrate and a superlattice with layers that alternated between positive and negative misfits were effective in reducing the density of threading dislocations. The superlattice was grown so as to minimize the number of dislocations which threaded through the superlattice to the growth surface. The thickness of each superlattice layer exceeded a critical thickness for bending threading dislocations into a network of interfacial dislocations, accompanied by mutual annihilation of the threading segments of the dislocations. This annihilation process took place at a finite rate, and benefited from the annealing of each layer of the superlattice before the next layer was grown. The thickness, annealing temperature and time were determined by the misfit between substrate and superlattice, and by the frictional forces on the dislocations. This process occurred mainly via glide, but could also occur via climb. When the number density of threading dislocations became sufficiently small, the probability of mutual annihilation was essentially negligible, and another type of superlattice could be used to further filter out the remaining dislocations. The second filter was a layer whose misfit with the underlying layer was of the same sign. Equations were developed which described the dislocation filtering process.

On the Use of Low Energy Misfit Dislocation Structures to Filter Threading Dislocations in Epitaxial Heterostructures. C.H.Simpson, W.A.Jesser: Physica Status Solidi A, 1995, 149[1], 9-20