Gas phase and surface modelling of diamond-like carbon deposition reactors

Among the methods used to prepare diamond-like carbon films, the deposition from rf glow discharges in hydrocarbon gases is the most common. Carbon deposits obtained by this technique vary from soft to hard, from highly resistive to conducting and from almost transparent to brown-yellow, depending on the process parameters. A large number of experimental studies has been published correlating the properties of the films with some easily accessible process parameters such as the total pressure, the gas flow rate, the gas mixture, and the d.c. bias. In particular the nature of gas and the substrate d-c bias have been found to play a crucial role for the film properties. In this context the modelling and the numerical simulation of the various physical and chemical processes occuring in the plasma phase and on the surface of the growing film can help the efforts in optimization and in scaling-up the plasma reactors. A methane discharge fluid model has been developed and subsequently combined with a simple chemical kinetic model