Local order studies of C-rich amorphous silicon–carbon thin films

Polymer-like hydrogenated amorphous carbon (a-C:H) films containing increasing concentrations of Si atoms (up to 12 at.%) have been grown using a dual-mode plasma (microwave and radiofrequency) plasma enhanced chemical vapor deposition reactor with low ion energies. X-ray emission and X-ray photoelectron spectroscopies (giving respectively Si 3p states and the total valence band states) have been used to probe the electronic structure. Complementary information on the local bonding have been obtained from the Si 2p and C 1s core levels. These results show that the Si bonding environments are consistent with Si–C4 units. The influence of the tetrahedrally bonded Si atoms on the C atom local environment is basically explained by a topological effect rather than a change in the C hybridization.