Films of W-Si-N were deposited by chemical vapor deposition, characterized, and compared to W-Si-N films deposited by physical vapor deposition, or sputtering. A range of different W-Si-N compositions were produced. The deposition temperature was low, 350 degrees C, and the precursors used are accepted by the semiconductor industry. Deposition rates are adequate for a diffusion barrier application. Resistivities range from 350 to 20,000 mu Omega cm, depending on composition. Step coverage of films with compositions expected to be of interest for diffusion barrier applications is 70-100% for aspect ratios of similar to 4 at similar to 0.25 mu, depending on composition. Films 1000 Angstrom thick with a composition W47Si9N44 were a effective barrier against Cu up to 700 degrees C.