Classical models of dislocation nucleation were presented and criticized. Two main points were then developed: emission of dislocations from surface steps and the role of point defects agglomeration on dislocation nucleation. Recent atomic simulation of half-loops emission from surface steps and experimental evidences of anisotropic relaxation of GaInAs films deposited on vicinal (111) GaAs substrates strongly support surface steps as preferential sites for nucleation. In low temperature buffer layer structures (SiGe/Si) an original dislocation structure was observed which corresponds to the dislocation emission in different glide systems by a unique nucleation centre.

Dislocation Nucleation in Heteroepitaxial Semiconducting Films. B.Pichaud, N.Burle, M.Texier, C.Alfonso, M.Gailhanou, J.Thibault-Pénisson, C.Fontaine, V.I.Vdovin: Physica Status Solidi C, 2009, 6[8], 1827-35