Orientational ordering of iron silicide films on sputter etched Si substrate

Sputter etching (SE) is a suitable treatment of Si surface to synthesize highly oriented β-FeSi2 films on the substrate, although SE produces amorphous layers in the surface. We have investigated the effect of surface amorphous layer on orientational ordering of formed β-FeSi2 and the optimum energy of Ne+ SE for highly oriented β-FeSi2 film. The energy ranges from 1 to 10 keV. The X-ray diffraction analysis clarified that amorphous layer prevents an epitaxial growth of β-FeSi2 film, and that post-irradiation annealing is effective to form highly oriented β-FeSi2 film, especially for low Ne+ energies. Transmission electron microscopy clarified that surface structure of Si substrate is epitaxially recrystallized with annealing after 3 keV SE, whereas polycrystalline surface forms with annealing after 10 keV SE. Low-energy SE and post-irradiation annealing is suitable for highly oriented β-FeSi2 film formation.