Epitaxial growth of NiSi2 on (111)Si inside 0.1–0.6 μm oxide openings prepared by electron beam lithography has been studied by field emission scanning electron microscopy, transmission electron microscopy, and thin-film stress measurement. Striking effects of size and shape of deep submicron oxide openings on the growth of NiSi2 epitaxy were observed. Epitaxial growth of NiSi2 of single orientation on (111)Si was found to occur at a temperature as low as 400 °C inside contact holes of 0.2 μm or smaller in size. Contact holes were found to be more effective in inducing the epitaxial growth of NiSi2 of single orientation than that of linear openings of the same size. The effects of size and shape of lateral confinement on the epitaxial growth of NiSi2 on (111)Si are correlated with the stress level inside oxide openings.

The formation and growth of CoSi2 inside 0.2–2 μm linear oxide openings and contact holes prepared by electron-beam lithography have been investigated. A thin, uniform epitaxial CoSi2 was grown inside 0.5 μm or smaller linear openings and 0.7 μm or smaller contact holes by both one- and two-step rapid thermal annealing processes. On the other hand, epitaxial and polycrystalline CoSi2 were found to form on silicon near the edge and central region, respectively, inside 0.6 μm or larger linear openings. The size effect of the oxide openings is correlated to the distribution of local stress induced at the oxide edge. The formation of CoSi at low temperature appeared to be retarded by the local compressive stress near the edge of the linear oxide openings. The relative ease in the epitaxial growth of CoSi2 near the oxide edge of the linear openings and of 0.7 μm and smaller contact holes is attributed to the thinness of the CoSi layer.

A triangleshaped nanoscale metal-oxide-semiconductor device

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