Deuterium-induced chemical erosion of carbon-metal layers

Magnetron-sputtered layers consisting of carbon and metal (W, Ti, V) were produced with 0–20 at.% metal concentration. The mixed layers were characterised by RBS, SEM, XRD and XPS, and exposed to D 3 + ions of 30 eV/D at temperatures between 77 and 1100 K. The chemical erosion yield was investigated by mass spectrometry and RBS. Above RT (∼300 K), the CD4 production yield for pure C layers exhibits a maximum around 750 K, which decreases with increasing metal concentration. For more than ∼3 at.% W, ∼6 at.% V and ∼7 at.% Ti, the maximum vanishes and the CD4 yield continuously diminishes with temperature. A decrease of the activation energy for ion-induced hydrogen release by adding dopants is responsible for the decrease. The CD4 yield at RT increases depending on metal and concentration, because the distribution of the erosion products is changed. Enrichment of metal on the surface with ion fluence is observed.