The effects of N2 and Ar as the ambient gas during rapid thermal annealing of tungsten silicide

This paper describes a study of rapid thermal annealing of amorphous tungsten silicide thin films (W0.62Si0.38 on Si at 11000C in Ar and N2 ambient gases. All films annealed in N2 exhibited good adhesion and remained smooth with no large grain growth. Films annealed in Ar showed grain nucleation and growth from the film perimeter until as critical stress was achieved, followed by stress-assisted grain growth. The resulting growth of large columnar grains caused the films to delaminate. Removal of the surface oxide/nitride layers from the silicide prior to annealing resulted in uniform nucleation and growth over the entire film during annealing in Ar, with no stress-assisted grain growth or film delamination. No difference, however, was observed during annealing in N2