Published online by Cambridge University Press: 17 March 2011
Dynamic Monte Carlo simulations with the binary collision approximation havebeen applied to the synthesis of hydrogenated amorphous carbon (a-C:H) films by plasma based ion implantation (PBII).We take as representative carbon carriers energetic CH3+ ions and CH3 radicals. The direct chemicalincorporation of the radicals, like CH3 reacting with a diamondsurface, is too low for the deposition of DLC films, so that the otherreaction mechanisms should be responsible. We assumed (a) completedissociation of CH3+ ions into one C atom and three H atoms with identicalvelocities upon bombarding the surface, (b) a unity and only one mono-layersticking of CH3 radicals on the surface, (c) incorporation(stitching) of H and C atoms under the surface induced by binary collisionswith energetic CH3+ ions, (d) release of H atoms by the dissociation of CH3 radicals on the surface, and (e) release of a part ofdisplaced H atom after the subsequent collision cascade. We also assumedonly the stitched carbon atoms form sp3 states and all othercarbon atoms form sp2 states. The effect of the target voltage onthe ion dose was also included. The effects of ion/neutral arrival ratio andion energy on the growth rate, the mixing layer thickness, the hydrogencontent, and the sp3/sp2 ratio in the deposited filmare presented.