The epitaxial quality of GexSi1−xfilms grown on Si⟨100⟩ by a novel laser‐assisted technique has been investigated for compositions in the rangex≤0.37 and thicknesses between 50 and 500 nm. Epitaxy is induced during electron beam deposition of GexSi1−xfilms on Si substrates by pulses of an excimer laser operating at 308 nm with 30 ns pulse duration. Good epitaxial growth is obtained for 50 nm films forx≤0.04 on chemically cleaned Si(100) surfaces even in the presence of substantial fluorine coverage. Using a predeposition/crystallization of a 50 nm pure‐Si buffer layer, good epitaxy is then obtained in 50 nm films forx=0.05–0.13. Atx=0.07, defect‐free alloys have been grown up to thicknesses of 0.5 &mgr;m. However, for films with compositions above 19 at.% Ge, dislocations at a nearly constant density of ≊10 &mgr;m/&mgr;m2are observed. This uniform density suggests a breakdown mechanism other than simple strain relaxation.