Mosaic structure of various oriented grains in CoSi₂/Si(001)

We investigated the mosaic structure of CoSi₂/Si(001) film in a synchrotron x-ray scattering experiment. The CoSi₂ film, formed by thermal reaction of a 120 Å Co film on Si(001), was composed largely of epitaxial grains of various orientations. In particular, the twin oriented (B-type) CoSi₂(111) grains were grown epitaxially on the Si{111} facets that were generated during annealing. Two distinct mosaic structures were observed in the CoSi₂ grains; the epitaxial grains of the same orientation with the Si substrate, such as the CoSi₂(001) [the CoSi₂(111)] grains lying on the Si(001) [the Si{111} facets], showed a small mosaicity of ∼0.5° full width at half maximum (FWHM), while those of different orientations demonstrated a rather broad mosaicity of ∼2.5° FWHM. We attributed the smaller mosaicity of the epitaxial grains of the same orientation to the reduced interfacial energy due to higher coincidence site density.