Effects of lateral confinement on the growth of CoSi and CoSi 2 on (0 0 1)Si inside 0.2–2 μm oxide openings prepared by electron beam lithography

Abstract

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