Silicide growth at metal surfaces: competition between subsurface diffusion and chemical reaction

Abstract

The nucleation and growth of silicide monolayers during deposition of Si on Pd(110) has been studied in situ by scanning tunnelling microscopy and vibrational spectroscopy of adsorbed CO. The growth scenario is found to depend strongly on the deposition temperature, which determines the competition between Si subsurface diffusion and silicide formation. With increasing temperature amorphous silicon (< 140 K), amorphous silicide (140–320 K) and crystalline palladium silicide (> 320 K) grows at the metal surface. Below 450 K the ordered silicide grows in strained islands while above 450 K strain is partially relieved through misfit dislocations.