The amorphous tungsten nitrides, WNx, film could be fabricated by reactive sputtering process. The nitrogen concentration for the amorphization ranges from 10 at% to 40at%. The amorphous film was crystallized into low resistivity -tungsten phase with equiaxed grains and excess nitrogen after the rapid thermal annealing for 1min at 1273K, which was similar to the resistivity of the sputtered pure tungsten film. The excess nitrogen was depleted from -tungsten crystals and then segregated at -tungsten/poly-Si interface. The segregated nitrogen has favored the formation of the homogeneous diffusion barrier layer comprised of silicon nitride, , nano-crystals, which undertaken the inhibition of the high resistivity tungsten silicide reaction.