Phase formation and morphological stability of ultrathin Ni-Co-Pt silicide films formed on Si(100)

Abstract

Ultrathin Ni, Co, and Pt films, each no more than 4 nm in thickness, as well as their various combinations are employed to investigate the competing growth of epitaxial Co1-yNiySi2 films against polycrystalline Pt1-zNizSi. The phase formation critically affects the morphological stability of the resulting silicide films, with the epitaxial films being superior to the polycrystalline ones. Any combination of those metals improves the morphological stability with reference to their parent individual metal silicide films. When Ni, Co, and Pt are all included, the precise initial location of Pt does little to affect the final phase formation in the silicide films and the epitaxial growth of Co1-xNixSi2 films is always perturbed, in accordance to thermodynamics that shows a preferential formation of Pt1-zNizSi over that of Co1-yNiySi2.