Specific features of formation and propagation of 60° and 90° misfit dislocations in GexSi1−x/Si films with x>0.4

Edge misfit dislocations in the GeSi/Si(001) pair: Conditions and specific features of high-quantity generation

“…2 was due to edge dislocations. We observed a similar relationship between 901 and 601 MDs in films grown under identical conditions on tilted Si substrates [5]. We are not aware of any previous publications reporting a high density of edge MDs in excess of the density of 601 MDs in GeSi films at the early stage of plastic strain relaxation.…”

“…So, the force approach and the energy approach yield identical values of h c for either type of MDs as it was discussed in general by Freund [17]. It was mentioned in [5] that formation of edge MDs in large amounts is most probable when 601 MDs arise in the film immediately after the critical film thickness h c for the formation of 601 MDs has exceeded. How 601 MDs can be introduced so early?…”

“…1from our paper[5] demonstrating the formation of Y-centers. The short dislocation segments seen in the dotted circles inFig.…”

“…A scheme of formation of edge MDs in GeSi films MBE-grown on Si substrates tilted in the tilt-axis direction was proposed in [5]. Let us extend this model to the case of stressed GeSi films grown on non-tilted Si (001) dislocation configuration comprising an extended edge MD and two dislocation segments, or threading dislocations (TDs) that pull this edge MD to both sides (see Fig.…”

“…This process can be called the mechanism of induced nucleation of 601 MDs. It was shown [5] that plastic relaxation of strained GeSi/Si(001) heterostructures with a large fraction of Ge could proceed under certain conditions mainly at the expense of edge MDs formed by the mechanism of induced nucleation of 601 MDs.…”