Epitaxial growth of Fe(001) on CoSi2(001)/Si(001) surfaces:: Structural and electronic properties

Ultrathin Fe films, in the thickness range 0-40 monolayers (ML), have been grown on Si(001) by molecular-beam epitaxy and characterized by low-energy electron diffraction, inelastic medium-energy electron diffraction, x-ray photoelectron spectroscopy, angular-resolved ultraviolet spectroscopy, x-ray photoelectron diffraction, ion scattering spectroscopy, and transmission electron microscopy. For Fe depositions onto Si(001) at room temperature, a disordered layer is obtained due to a high degree of intermixing between the Fe deposit and the Si substrate. Successful epitaxial growth of Fe at room temperature is achieved by use of a thin (similar to 10 Angstrom) CoSi2 silicide interlayer epitaxially grown on the Si(001) substrate prior to the Fe deposition, which prevents the intermixing of the Si substrate atoms into the Fe overlayer. Below a coverage of similar to 2 ML a reacted ordered iron-rich phase forms at the surface. At higher coverages, there is growth of an epitaxial essentially body-centered cubic (bcc) Fe(001) overlayer with the orientational relationships Fe(001)[001]parallel to CoSi2(001)[001]parallel to Si(001)[001]. Finally, a well-ordered Fe/CoSi2 interface is formed even at room temperature. [S0163-1829(99)12335-X].