Real-time monitoring, growth kinetics and properties of carbon based materials deposited by sputtering

Abstract

The nucleation stages of growth of carbon-based materials such as amorphous carbon (a-C) and carbon nitride (a-CN x ) films control the bonding configuration, sp 2 and sp 3 formation, N concentration in a-CN x films and consequently their final properties. Thus, in order to obtain insights into the deposition mechanisms, the study of growth kinetics by applying real-time monitoring is required. We present here, the development of a-C and a-CN x thin-films by conventional and unbalanced magnetron sputtering, studied by in situ spectroscopic ellipsometry (SE) and multi-wavelength ellipsometry (MWE) in the energy region 1.5–5.5 eV. SE and MWE were used to monitor the deposition processes and to study the films properties. The MWE provides the ability for simultaneous acquisition of the dielectric function, in 16 different wavelengths distributed in the VIS-UV energy region and to investigate the nucleation and growth stages, the deposition rate and films composition, as well as their optical properties during deposition. The results deduced either by real-time MWE monitoring, or by the analysis of in situ SE and MWE data, for the carbon based materials prepared by the above techniques, were certified by X-ray reflectivity studies and were correlated to various mechanisms taking place during film growth (e.g. diffusion, surface adsorption, chemical reactions, etc.), which were investigated by applying a phenomenological model of growth kinetics.