CRYSTAL-STRUCTURE, MORPHOLOGY AND COMPOSITION OF MAGNETRON SPUTTERED TUNGSTEN CARBIDE FILMS

It is shown that small variations of the deposition parameters during magnetron sputtering of tungsten carbide thin films may result in drastic changes of film properties. An increasing working gas pressure for example lowers stress and hardness values. Simultaneously, the texture of the beta-WC1-x cristallites turns from <200> preferential orientation to <111>, whereas the composition of the films does not change. In reactive sputtering with a tungsten target there is a narrow range from 2 to 3% C2H2 gas admixture to the working gas where the films are stochiometric (WC) and hard, and grain size and morphology are similar to that of non-reactively sputtered films. The generation of different crystallite structures and orientations in the range of 0-3% C2H2 admixtures are used to produce a multiphase thin film with extremely low crack propagation.