GROWTH-CHARACTERISTICS OF TUNGSTEN-CARBON FILMS DEPOSITED BY MAGNETRON SPUTTERING

Tungsten and tungsten-carbon films have been deposited by direct and r eactive magnetron sputtering in pure Ar and Ar-CH4 mixtures, respectiv ely. The structural properties of W and W-C/substrate samples were inv estigated by cross-sectional transmission electron microscopy, concent rating on the structure of the interface regions. Both pure tungsten a nd tungsten-carbon films exhibit a regular columnar structure, but in the case of carbon-doped films, growth begins by the formation of a na nocrystalline alpha-W structure. At a certain film thickness, dependin g on the amount of the incorporated carbon, the growth of the films ch anges to the formation of a polycrystalline columnar structure. The ca rbon content is higher in the nanocrystalline part of the film, which is always present independently of the applied substrate material. (C) 1998 Published by Elsevier Science S.A.