HARDNESS AND ELASTICITY OF DIAMOND-LIKE CARBON-FILMS PREPARED BY ION-BEAM-ASSISTED SPUTTER-DEPOSITION

Hardness H and Young's modulus Y of non-hydrogenated amorphous carbon (a-C) films have been determined by an ultra-low-load depth-sensing nanoindenter to examine their dependence on the energy and momentum transferred to a depositing carbon atom by an assisting argon-ion beam. The results indicate that the film formation process is momentum-transfer controlled. Amorphous carbon films were prepared and analyzed by a new procedure: the ion-beam sputter-deposited film was assisted by a focused argon-ion beam. This method produces a film with a high central zone and progressively decreasing zones of energy and momentum transfer. By measuring H and Y in these different regions, a large data set was obtained from just one film. From the analysis of two films which were prepared at different assisting ion-beam voltages of 100 and 300 V, it was found that H and Y display a uniform functional dependence only if plotted vs. momentum transfer.