A method of forming a conductive metal silicide by reaction of metal with silicon is described. A method includes providing a semiconductor substrate with an exposed elemental silicon-containing surface. At least one of a nitride, boride, carbide, or oxide-comprising layer is atomic layer deposited onto the exposed elemental silicon-containing surface to a thickness no greater than 15 Angstroms. This ALD-deposited layer is exposed to plasma and a conductive reaction layer including at least one of an elemental metal or metal-rich silicide is deposited onto the plasma-exposed layer. Metal of the conductive reaction layer is reacted with elemental silicon of the substrate effective to form a conductive metal silicide-comprising contact region electrically connecting the conductive reaction layer with the substrate. Other aspects and implementations are contemplated.