Au-assisted Co silicide island growth on Si(1Â 1Â 1)

► Au is known to favor the formation of CoSi2 by solid phase reaction of Co with Si. ► We investigated the formation of Co silicide islands in presence of Au-rich islands. ► Au-rich islands induce locally an extraction of Si atoms out of the substrate. ► Si atoms outdiffusion decreases the formation temperature of Co silicide islands.