Influence of particle energies on the properties of magnetron sputtered tungsten films

Abstract Tungsten films were produced on Ti 6 Al 4 V substrates by DC magnetron sputtering 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 flux deposited by the different particles during the film growth was investigated from substrate temperature measurements. With the aid of calculation models and knowing the deposition parameters, we determined the contribution of the different species in the total energy arriving on the growing film. Using krypton sputtering gas instead of argon mainly decreased both energy and flow of the reflected neutrals. The residual stresses in the films were determined by a beam curvature technique, the hardness was measured by Vickers microindentation and inert gas content in the films was analyzed by electron probe microanalysis. The inert gas incorporation in the growing film was found to be dependent on the energetic neutral bombardment. Growth-induced film compressive stresses were minimal with pure krypton (−1.2GPa) and increased up to −3.2 GPa in pure argon. An increase of film hardness from 8.2 GPa in krypton atmosphere to 16.8 GPa in argon was also observed.