Ironsilicide formation by high temperature codeposition of Fe-2Si with different thicknesses on Si (111)

Fe and 2Si were co-deposited on Si (111) surface at 853 K. The formation of silicides was investigated by Mossbauer spectroscopy and electron microscopy. Depending on the thickness of the deposited films different phases were formed. At low thickness, stable $ϵ$-FeSi (B20) and metastable [CsCl]-Fe${}_{1-x}$Si (B2) phases were observed. In the latter case, because of the presence of Fe vacancies in the lattice the local symmetry around the iron components was lower than cubic. At larger (12 nm) deposited thickness, stable $\beta$-FeSi${}_2$ has been formed.