A new source for the heterogeneous nucleation of 60-type misfit dislocations in this material was observed here for the first time. It was found to consist of Frank-type partial dislocations which bounded stacking faults that were induced by N doping in the initial stages of growth. Some of the Frank partials also acted as pinning centers and produced threading dislocations in relaxed N-doped ZnSe/GaAs heterostructures. Studies which involved in situ electron beam induced heating were carried out in order to observe the strain relaxation mechanism in the epitaxial layers. These studies revealed that, by dissociation of an (a/3)<1¯11> Frank partial dislocation on the (1¯11) plane, an (a/2)<101> 60º mixed dislocation and an (a/6)<¯1¯2¯1> Shockley partial dislocation were produced. The Shockley partial dislocation expanded along the faulted plane and interacted with the (a/3)<¯11¯1> Frank partial dislocation in the fault. This interaction produced a second segment of (a/2)<¯10¯1> 60º mixed dislocation. The two 60º mixed dislocation segments glided on a (¯111)-type plane until they reached the interface and formed 60º interfacial misfit dislocations with 2 threading segments. Thus, after strain relaxation was fully achieved, a regular array of 60º misfit dislocations, attached to some non-dissociated Frank partial dislocations, was present at the N-doped ZnSe/GaAs interface in samples in which the film thickness was greater than a critical value.

L.H.Kuo, L.Salamanca-Riba, J.M.DePuydt, H.Cheng, J.Qiu: Philosophical Magazine A, 1994, 69[2], 301-13