Surfactant-mediated growth of Si1-xSnx layers by molecular-beam epitaxy

1-x

Sn_x (0.01≤x≤0.04) layers on Si(001) and relaxed Si-Ge substrates. The Si_1-xSn_x layers were investigated using Rutherford backscattering spectrometry, atomic force microscopy, transmission electron microscopy and preferential-etching experiments. The investigation of surfactant-mediated growth of epitaxial Si_1-xSn_x was motivated by a possible use of relatively higher growth temperatures without relaxation by surface precipitation. It is demonstrated that higher growth temperatures are attainable when Bi is used as surfactant if the surface-segregated Sn layer is relatively small, equivalent to Si_1-xSn_x layers of low strain. The increase in growth temperature leads to a significant improvement in the crystalline quality of these Si_1-xSn_x layers.