engleski

Surface characterization of carbon-tungsten alloys prepared by reactive sputtering

The surface features of tungsten-carbon thin films, deposited onto monocrystalline silicon substrates by reactive magnetron sputtering (argon + benzene) has been investigated by GISAXS, AFM and SEM. Benzene partial pressure was varied from 1% to 10% of the total working gas pressure in order to produce W-C films with variable fraction of incorporated unbound carbon. A series of samples were prepared, with the substrate temperature held at RT, 200°C, and 400°C, and the substrate potential held at floating potential or biased -70 V with respect to discharge plasma. Structure of the films is found to be nanocrystalline to amorphous WC1-x as the carbon content increase, with a fine dispersion of DLC-clusters imbedded between nanograins. The GISAXS analysis revealed the particle size of about 3 nm within the films. The same results indicate that the surface of the examined films is rather smooth - surface roughness is about 0, 5 nm, with a very short inplane height-height correlation length. The AFM measurements and SEM results are employed to characterize the surface and subsurface layer of the films, in order to examine a degree of bulk structure propagation to the surface.

carbon-tungsten alloys ; reactive sputtering ; surface characterization

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