Characterization of ultrathin CoSi sub 2 on Si(111) layers.

Ultrathin epitaxial CoSi sub 2 films on Si(111) have been grown in ultrahigh vacuum by room temperature deposition of Co on Si(111) followed by a high temperature anneal at ~600C. Characterization of the thin films with transmission electron microscopy has revealed pseudomorphic growth up to thicknesses ~30angstroms. Pinholes present in the pseudormorphic thin films are thought to prevent the trapping of dislocations within the film. A clear transition to films containing a regular network of misfit dislocations occurs at ~40angstroms. Evidence for the growth of CoSi sub 2 via intermediate metal-rich silicide phases is observed.