Both binary metal nitrides MxNy and ternary metal silicon nitride MxSiyNz (where M may be titanium, zirconium, hafnium, tantalum, molybdenum, tungsten and other metals; and x, y, and z represent different quantitative combinations of metal, silicon, and nitrogen that may be used) may be used as the metal nitride 206 in the barrier layer. [0056] When tungsten is employed as the metal component in t