A misfit relaxation mechanism was proposed which could occur during the growth of highly misfitting layers. It was based upon a misfit-compensating distribution of physical point strain sources, at the interface between the layer and substrate, instead of upon misfit dislocations. These point strain sources consisted of interfacial islands (misfit grainlets) which had a lattice misfit that was opposite in sign to that of the surrounding epitaxial layer. In most cases, this was brought about by an orientation relationship that was different to that which the surrounding layer had with the substrate. The strain-relaxing effectiveness of misfit grainlets was demonstrated by means of an analysis of the interface structure of GaN on sapphire. The formation of misfit grainlets was explained in terms of a self-organized island growth process.

Point Strain Sources which Compensate Misfit during Epitaxial Growth. M.Albrecht, S.Christiansen, H.P.Strunk: Applied Physics Letters, 1997, 70[8], 952-4