Modeling of ta-C growth: Influence of the technological parameters

The structure of tetrahedral bonded amorphous carbon (ta-C) is determined by the energy of the impinging carbon ions, the angle of incidence, the substrate temperature and the deposition rate. Up to now modeling of the ta-C growth was concentrated on the energy effects by investigating the early stages of the ion impact and the short-time relaxation in the thermal spike. A new analytical model is presented, which emphasizes the role of long-time diffusion, driven by the stress induced drift towards the surface. In accordance with the experimentally found trends, the model allows the estimation of the sp3 content in dependence on the technological relevant deposition parameters ion energy, angle, temperature, rate and their distributions. This opens the way for the realistic simulation of ta-C growth in industrial coaters.

Research highlights
► Description of the long-time relaxation of the ta-C growth within an analytical model.
► Dependence of the sp3 content on the relevant technological parameters.
► Ion beam parameters include energy, energy distribution, angle of incidence, rate.
► Substrate parameters embrace temperature, heat dissipation.
► Demonstration for industrial coaters with rotating carriers: Formation of multilayers.