Reduction of dislocations in multilayer structures of zinc-blend materials

Abstract

Described is a procedure for virtually eliminating disclocations in multilayer structures of materials having a crystallographic zinc-blend structure, in particular quaternary layers of Al.sub.y Ga.sub.1.sub.-y As.sub.1.sub.-z P.sub.z grown on Al.sub.x Ga.sub.1.sub.-x As substrates (y > x .gtoreq. 0). By carefully controlling the quaternary layer thickness and the lattice parameter mismatch at the growth temperature, it is possible to change the direction of substrate dislocations as they enter the substrate/layer interface. The length of the dislocation in the interfacial plane can be extended so that it is "infinitely" long, i.e., it reaches the edge of the wafer. As a result, the epitaxial quaternary layer and all layers subsequently grown thereon will be virtually dislocation free, provided that the thickness, stress and uniformity of the layers are such that no surface dislocation souces are activated. Also described are double heterostructure junction lasers with reduced values of both stress and dislocations.

Dependencies are inferred from the claim text.