We present a scanning tunneling microscopy study of the initial stages of epitaxial Si overgrowth of CoSi2(111) films. Under suitable growth conditions the silicon was found to decorate the steps of the silicide. This opens up the possibility of creating arrays of parallel silicon wires on a CoSi2 substrate. After oxidation of the silicon by exposing it to air the silicide in between the wires can be removed by wet etching, leaving an array of expitaxial CoSi2 wires. The mechanism leading to the formation of the silicon wires was identified as strongly enhanced diffusion of adatoms on a silicide surface compared to a silicon surface and preferential nucleation on upward steps.