Effect of Al interlayers on two-step epitaxial growth of CoSi 2 on Si(1 0 0)

Abstract

We have performed the two-step epitaxial growth of CoSi 2 on Si(1 0 0) surfaces with Al interlayers. Microstructures of the surface and the interface during the growth have been investigated by scanning tunneling microscopy and transmission electron microscopy (TEM). At the first-step growth, the introduction of an 1-monolayer (ML)-thick Al interlayer prior to a 3-ML-thick Co layer deposition on the Si clean surface results in the formation of two dimensional islands of epitaxial CoSi 2 with higher coverage, compared to the case without the Al interlayer. Cross-sectional TEM observations revealed atomically-flat CoSi 2–Si interfaces. At the second step, CoSi 2 is epitaxially grown on these islands that acts as a template layer. In-depth growth of CoSi 2 domains is also observed to occur forming {1 1 1} facets at the CoSi 2–Si interfaces. Effects of the Al interlayer on the growth morphology of epitaxial CoSi 2 are discussed.