Detailed analyses of Burgers vectors and line directions were carried out on 3 types of dislocation defect (so-called X, Y and single-loop) which formed in low-misfit GeSi/Si(001) heterostructures which were grown under conditions of planar interface growth. The X-type and Y-type defects originated from small prismatic vacancy half-loops which nucleated at visible precipitates in the strained-layer/Si-substrate interface. The single-loop defects also originated from small vacancy-like half-loops which usually nucleated at the interface, but sometimes within the strained layer. After growth, none of the dislocations lay in glide planes, and all 3 dislocation structures had to transform into glissile configurations before they could generate strain-relieving dislocations. The mechanism which controlled this sessile/glissile transformation was climb via vacancy absorption. This corresponded to the nucleation stage for the generation of misfit dislocations, and was consistent with experimental results which had demonstrated a reduction in the nucleation rates during rapid thermal anneals following Si irradiation of the as-grown samples at room temperature.

Climb/Glide Dislocation Sources at Low-Misfit GexSi1-x/Si(001) Interfaces. S.Jiao, P.B.Hirsch, D.D.Perovic: Philosophical Magazine A, 2001, 81[5], 1041-64