Microstructural characterization of thin carbon films deposited from hydrocarbon mixtures

The connection between film microstructure and deposition conditions has been studied extensively for a variety of hydrocarbon precursors. This work focuses on carbon deposition by chemical vapor deposition from hydrocarbon mixtures and shows a simultaneous improvement in growth rate and film microstructure for specific gas combinations. Mixtures of acetylene, butane, methane and propane are used at concentrations between 20 and 100% to exploit the individual advantages of each precursor. Raman spectroscopy generally shows an isotropic pyrolytic carbon, with well-defined graphitic features. The degree of graphitization and the level of crystalline order are directly related to the deposition conditions used. The effect of the substrate temperature, precursor species, and the precursor concentration on growth kinetics and microstructural features are discussed in detail. Environmental scanning electron microscopy studies typically show an improvement in deposition rate with precursor concentration and substrate temperature for the range of deposition conditions considered.