The surface morphology of graded layers was studied using atomic force microscopy and transmission electron microscopy. The effect of dislocation gliding, in the layer, upon the cross-hatching pattern indicated that the origin of cross-hatching could be attributed to misfit dislocations which lay mainly in the graded layer. The various mechanisms which were involved in the formation of surface cross-hatching in relaxed graded layers have been reviewed. It was concluded that the cross-hatching was definitely not related to threading dislocations, but only to the misfit dislocation length in the layer. The surface free energy then determined the amplitude of the cross-hatching.

Influence of Misfit and Threading Dislocations on the Surface Morphology of SiGe Graded Layers B.Gallas, J.M.Hartmann, I.Berbezier, M.Abdallah, J.Zhang, J.J.Harris, B.A.Joyce: Journal of Crystal Growth, 1999, 201-202, 547-50