Formation of the polycrystalline FeSi phase with the CsCl structure in codeposited thin FexSi1 − x films (x = 0.5–0.6)
Specific features of the phase formation in the Fe-Si system within the FexSi1 − x (x = 0.5–0.6) concentration range have been investigated. The data obtained by conversion electron Mössbauer spectroscopy suggest that, for the Fe-Si system in the concentration range x > 0.55, a polycrystalline FeSi phase with the CsCl structure is formed under thermodynamically equilibrium conditions upon annealing at T = 250°C; in this case, the excess (overstoichiometric) Fe atoms are incorporated into the Si sublattice. Previously, the CsCl-FeSi phase was observed only in epitaxially stabilized FeSi/Si(100) layers.