A study was made of the interplay between elastic and plastic strain relaxation in SiGe/Si(001). It was shown that the formation of cross-hatched patterns was the result of a strain relaxation process that involved 4 sequential stages. These were elastic strain relaxation by surface ripple formation, the nucleation of dislocations at the rim of the substrate (followed by dislocation glide and deposition of a misfit dislocation at the interface), a locally enhanced growth rate at the strain-relaxed surface above the misfit dislocations (resulting in ridges that then formed a cross-hatched pattern which relaxed the strain elastically), and the preferred nucleation and multiplication of dislocations in the troughs of the cross-hatched pattern (due to strain concentrations). The preferred formation of dislocations again resulted in locally enhanced growth rates in the trough, and thus led to smoothing of the growth surface.

M.Albrecht, S.Christiansen, J.Michler, W.Dorsch, H.P.Strunk, P.O.Hansson, E.Bauser: Applied Physics Letters, 1995, 67[9], 1232-4