INFLUENCE OF DEPOSITION CONDITIONS ON THE MORPHOLOGY OF SPUTTERED W-C-(CO) FILMS

W-C-(Co) films were deposited on HSS substrates by non-reactive r.f. and d.c. sputtering from sintered WC targets with 0, 6 and 15 wt.% Co. The morphology of the coatings was studied by SEM as a function of discharge pressure and power and substrate bias. In addition to the usual morphologies found in sputtered films (types 1 and T), featureless films which were not predicted by Thornton's model were also obtained at low deposition pressure and/or high substrate bias. Some modifications to this model are consequently proposed. Increasing the discharge power leads to less dense films. For certain deposition conditions, a characteristic surface roughness was obtained as a result of the evolution of argon gas incorporated in the film during deposition.