Film thickness effect on the epitaxial growth of CoSi 2 on Si(111)

Abstract

Effects of deposited cobalt film thickness on the epitaxial growth of CoSi 2 on Si(111) by the solid phase epitaxy regime have been studied using transmission electron microscopy. Thinner films (30 Å) facilitate the growth of epitaxial CoSi 2, the formation of smooth silicide-Si interfaces and even the growth of single-crystal CoSi 2 at low annealing temperatures, but degrade in thermal stability. Thicker films (300 Å) retard the grain realignment, and yield faceted epitaxial structure after high temperature annealing. Hence, film thicknesses sufficient to benefit from easy epitaxial growth and forming flat silicide-Si interfaces and yet are thermally stable should be used. Accordingly, a facet-free, thermally stable, single-crystal CoSi 2 structure has been achieved using 100 Å thick films.