The invention includes methods of forming conductive metal silicides by
reaction of metal with silicon. In one implementation, such a method
includes providing a semiconductor substrate comprising an exposed
elemental silicon containing surface. At least one of a crystalline form
TiN, WN, elemental form W, or SiC comprising layer is deposited onto the
exposed elemental silicon containing surface to a thickness no greater
than 50 Angstroms. Such 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. At least one of
metal of the conductive reaction layer or elemental silicon of the
substrate is diffused along columnar grain boundaries of the crystalline
form layer effective to cause a reaction of metal of the conductive
reaction layer with elemental silicon of the substrate to form a
conductive metal silicide comprising contact region electrically
connecting the conductive reaction layer with the substrate. Other
aspects and implementations are contemplated.