DEPOSITION OF HYDROGENATED CARBON LAYERS FROM CH3-BEAMS( ION)

Carbon deposition and hydrogen codeposition is investigated as functio n of ion energy, fluence and target temperature at normal incidence by bombardment of hydrocarbon molecules onto Si and graphite. An amorpho us hydrogen/carbon (a-C:H) layer is formed in a thickness range of 40 to 130 nm by CH3+ bombardment up to a fluence of 3 x 10(18)/cm(2). The deposition process and the re-erosion phenomenon of the carbon film i s also studied. The experimental results are compared with TRIDYN comp uter simulation and previous experimental results of carbon sputtering by atomic H+ and C+ beams in order to have a good understanding of th e interaction between hydrocarbon molecular ions and the carbon-based wall in fusion devices.