The dislocation structure at the initial stage of relaxation of GexSi1−x films (x ∼ 0.4–0.8) grown on Si(001) substrates tilted at 6° to the nearest (111) plane was studied. One of the directions along which edge dislocations were formed was no longer in the plane of the interface but crosses the latter at the angle of miscut. Therefore, long edge misfit dislocations could not exist in the direction of substrate misorientation, because their ends moved away from the interface during dislocation propagation. Two different mechanisms of formation of short segments of edge (90°) misfit dislocations in the direction of substrate misorientation were found. The first mechanism was the correlated nucleation of complementary 60° dislocation half-loops manifested in the form of the so-called Y-center consisting of a short segment of the 90° misfit dislocation and 60° misfit dislocations diverging from this segment in form of two rays in the miscut direction. In the second mechanism, the 90° misfit dislocation segment was formed owing to intersection of already existing complementary 60° misfit dislocations slipping in mirror-like inclined planes {111}. Samples annealed at higher temperatures contained misfit dislocation segments, which lose their contrast on one of the TEM images taken to detect edge dislocation segments in the two-wave diffraction mode but did not coincide with the direction [110] (they pass along the intersections of the mirror-like inclined planes {111} with the surface of the misoriented Si substrate). To explain this phenomenon, a model was proposed, where one of the pair of complementary 60° misfit dislocations propagating at an angle to each other continuously approaches the other by the cross-slip mechanism. Formation of a chain of edge misfit dislocation segments connected by a pair of 60° misfit dislocations became possible. The averaged direction of such a dislocation structure coincides with the direction of one of the 60° misfit dislocations.

Formation of Edge Misfit Dislocations in GexSi1-x(x ≈ 0.4–0.8) Films Grown on Misoriented (001)→(111) Si Substrates: Features before and after Film Annealing. Y.B.Bolkhovityanov, A.S.Deryabin, A.K.Gutakovskii, L.V.Sokolov: Journal of Applied Physics, 2010, 107[12], 123521