Nucleation of Misfit Dislocations in Strained-Layer Epitaxy in the Ge sub x Si sub (1-x) /Si System.

We describe theoretical and experimental investigations of the nucleation of lattice mismatch-accommodating dislocations in strained Ge sub x Si sub (1-x) /Si(100) system. In the Ge sub x Si sub (1-x) /Si(100) system, activation barriers for heterogeneous nucleation of dislocation half-loops at the growth surface decline dramatically with increasing lattice mismatch (higher x). At lower mismatches, misfit dislocation nucleation appears to be associated with growth defects, whilst at higher x surface loop nucleation is favoured.