Interaction of hydrogen plasma with carbon–tungsten composite layer

Abstract: Interaction of neutral hydrogen atoms with the layer of hydrogenated carbon–tungsten composite was studied. A 1μm thick layer was prepared by sputter deposition from C and WC-targets in Ar/C2–H2 gas mixture. After deposition the samples were treated in weakly ionized highly dissociated hydrogen plasma created in a microwave discharge at a power of 1kW. The gas flow was 13l/h and pressure was 90Pa. Temperature of the samples during treatment was about 850K. After plasma treatment the samples were analyzed by AES (Auger electron spectroscopy) depth profiling, XPS (X-ray photoelectron spectroscopy) and SEM (scanning electron microscopy). It was found that during hydrogen plasma treatment selective etching of the C–W layer occurred. Carbon was preferentially removed from the C–W layer, and after about 10min of treatment practically only tungsten with a huge porosity was detected. [Copyright &y& Elsevier]