INFLUENCE OF PARTICLE ENERGIES ON THE PROPERTIES OF MAGNETRON-SPUTTERED TUNGSTEN FILMS

Tungsten films were produced on Ti6Al4V substrates by DC magnetron spu ttering in either argon or krypton atmosphere at an absolute pressure of 0.16 Pa and at a low substrate bias of -25 V. The total heating flu x deposited by the different particles during the film growth was inve stigated from substrate temperature measurements. With the aid of calc ulation models and knowing the deposition parameters, we determined th e contribution of the different species in the total energy arriving o n the growing film. Using krypton sputtering gas instead of argon main ly decreased both energy and flow of the reflected neutrals. The resid ual stresses in the films were determined by a beam curvature techniqu e, the hardness was measured by Vickers microindentation and inert gas content in the films was analyzed by electron probe microanalysis. Th e inert gas incorporation in the growing film was found to be dependen t on the energetic neutral bombardment. Growth-induced film compressiv e stresses were minimal with pure krypton (-1.2 GPa) and increased up to -3.2 GPa in pure argon. An increase of film hardness from 8.2 GPa i n krypton atmosphere to 16.8 GPa in argon was also observed. (C) 1998 Published by Elsevier Science S.A.