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We present a detailed analysis of the point-defect clustering in strained Si/Si 1Ϫx Ge x /(001)Si structures, including the interaction of the point defects with the strained interfaces and the sample surface during 400 kV electron irradiation at room temperature. Point-defect cluster formation is very sensitive to the type and magnitude of the strain in the Si and Si 1Ϫx Ge x layers. A small compressive strain (Ϫ0.3%) in the SiGe alloy causes an aggregation of vacancies in the form of metastable ͓110͔-oriented chains. They are located on ͕113͖ planes and further recombine with interstitials. Tensile strain in the Si layer causes an aggregation of interstitial atoms in the forms of additional ͓110͔ rows which are inserted on ͕113͖ planes with ͓001͔-split configurations. The chainlike configurations are characterized by a large outward lattice relaxation for interstitial rows (0.13 Ϯ0.01 nm) and a very small inward relaxation for vacancy chains (0.02Ϯ0.01 nm). A compressive strain higher than Ϫ0.5% strongly decreases point-defect generation inside the strained SiGe alloy due to the large positive value of the formation volume of a Frenkel pair. This leads to the suppression of point-defect clustering in a strained SiGe alloy so that SiGe relaxes via a diffusion of vacancies from the Si layer, giving rise to an intermixing at the Si/SiGe interface. In material with a 0.9% misfit a strongly increased flow of vacancies from the Si layer to the SiGe layer and an increased biaxial strain in SiGe both promote the preferential aggregation of vacancies in the ͑001͒ plane, which relaxes to form intrinsic 60°dislocation loops.

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The solid-phase crystallization process in thin amorphous silicon films on glass substrates was studied with application of excimer laser annealing (ELA) and rapid thermal annealing (RTA) for stimulation of nucleation. Use of ELA allowed us to create homogeneous polycrystalline silicon films on glass with grain sizes up to 3 µm at temperatures below 550 • C. Use of RTA reduced the incubation time of nucleation from 100 to 6 h. The textured silicon films on glass with predominant orientation (110) and sizes of textured areas up to 30 µm were manufactured using excimer laser stimulation of nucleation. The influence of the mechanical stress mechanism on grain orientation was suggested, and it was theoretically shown that internal stresses retard the nucleation process. The addition of deformation to the chemical potential difference was estimated for nucleation in amorphous silicon as 11.4 meV per nucleated atom.

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The initial stages of point defect cluster formation on {111} habit planes in Si crystals have been investigated during in situ electron irradiation in a high resolution electron microscope to elucidate their nature and origin. It was observed that k 110 l interstitial chains located in {111} planes at regular spacing are formed by the agglomeration of self-interstitial atoms to the core of vacancy or interstitial Frank partial dislocation loops and by the insertion of interstitial chains between two perfect {111} planes. Based on experimental and calculated high resolution electron microscopy images a structural model for the {111}-defect is proposed which includes a regular sequence of double ® ve-membered and single eight-membered rings in which no dangling bonds are involved. A dependence of the displacement vector of the {111}-defect on the formation mechanism is observed. An isolated {111}-defect is characterized by the fully relaxed atomic structure with a displacement vector of ( a /5 ) k 111 l . The aggregation of self-interstitials in the core of Frank partial dislocations results in the relaxation of the strongly deformed crystal lattice by decreasing the displacement vector of initial defects. §