Surface and interface structure of epitaxial CoSi2 films on Si(111)

Abstract

The surface and interface structures of molecular beam epitaxially grown CoSi2 films on Si(111) have been studied by scanning tunneling microscopy and by transmission electron microscopy, respectively. All surfaces are found to be inhomogeneous, exhibiting (2×1) and (2×2) reconstructed domains along with unreconstructed areas, depending on their stoichiometry. All of them could be imaged with atomic resolution. The surface step structure and the formation of pinholes have been examined for a wide range of growth conditions. Evidence is presented for micron-scale surface diffusion of Si on CoSi2 at temperatures as low as 800 K. The interface step structure, studied by transmission electron microscopy, has been found to depend critically on the details of the growth procedure.