The structural properties of single-layer heterostructures which consisted of SiGe which had been grown onto (001) Si or (111) Ge

substrates, were studied by means of optical microscopy, chemical etching and plan-view and cross-sectional transmission electron microscopy. An analysis of the compositional dependence of the threading dislocation density in the epitaxial layers was carried out, and showed that the dislocation structure in such heterostructures formed as a result of the concerted operation of various misfit dislocation generation and multiplication mechanisms. In heterostructures with a lattice mismatch of up to 1%, the multiplication (via the Frank-Read mechanism) of misfit dislocations at the interface played a pivotal role in misfit strain relief.

V.I.Vdovin, M.G.Milvidskii, T.G.Yugova: Solid State Phenomena, 1996, 47-48, 497-502