Hydrogen retention in carbon–tungsten co-deposition layer formed by hydrogen RF plasma

Abstract

Carbon–tungsten co-deposition layers (C–W layers) were formed by sputtering method using hydrogen or deuterium RF plasma. The deposition rate of the C–W layer by deuterium plasma was faster than that by hydrogen plasma, where the increase of deposition rate of tungsten was larger than that of carbon. This indicates that the isotope effect on sputtering–depositing process for tungsten is larger than that for carbon. The release curve of hydrogen from the C–W layer showed two peaks at 400 °C and 700 °C. Comparing the hydrogen release from the carbon deposition layer and the tungsten deposition layer, it is considered that the increase of the release rate at 400 °C is affected by tungsten and that at 700 °C is affected by carbon. The obtained hydrogen retention in the C–W layers which have over 60 at.% of carbon was in the range between 0.45 and 0.16 as H / (C + W).