Characterization of FeSix film by codeposition on β-FeSi2 template

We report the characterization of FeSix (x∼3) thin film prepared by simultaneous electron beam evaporation of Fe and Si onto a β-FeSi2 template at 250°C. The in situ reflective high energy electron diffraction observation and ex situ cross-section transmission electron microscope characterization of the as-deposited film imply that the as-deposited film has the structure similar to that of β-FeSi2. But the spreading resistance measurement shows that the film is metallic. Auger electron spectroscopy suggests that the chemical environment of Fe atoms in the as-deposited FeSix film is different from that in the annealed film (β-FeSi2 film). We explain this paradox by assuming that the as-deposited film has the crystal lattice similar to β-FeSi2 but with ingredient disorder due to the low transport viscosity of Fe and Si atoms at this temperature.