How is the chemical bonding of W-Si-N sputtered coatings?

Thin films of W-Si-N, deposited by reactive magnetron sputtering, were inve stigated using X-ray photoelectron spectroscopy (XPS). The objective of thi s research work was to study the chemical binding state of these coatings. During the sputtering process, the established atomic bonds may possibly no t agree to the elemental bonding preview using the values of chemical affin ity, which decrease for Si-N, Si-W to W-N bonds. XPS data show that in W-ba sed films which have simultaneous additions of Si and N, a Si-N type is the preferential bond established. This behaviour is confirmed either by the e volution of the Si/W atomic ratio of the as-deposited coatings, which incre ase with the N content, or the variation of the lattice parameters of the b .c.c. alpha -W phase for W-N, W-Si and W-Si-N systems. However, since no co mpound of silicon nitride was detected, it was concluded that this phase, f ormed by specific contents of Si and N must have been present in the W-Si-N films in the amorphous state. (C) 2001 Elsevier Science B.V. All rights re served.