Characterization of amorphous hydrogenated carbon films deposited from CO–C2H2 mixtures in a distributed ECR plasma reactor

Amorphous hydrogenated carbon (a-C:H) films have been deposited on silicon substrates at the floating potential from CO–C2H2 mixtures using a distributed electron cyclotron resonance (DECR) plasma reactor. The deposition rate of films and chemical composition determined by X-ray photoelectron spectroscopy (XPS) were investigated as functions of the CO concentration in the gas phase. The concentration of CC, CO and CO bonding configurations in the films was deduced from XPS measurements. The hybridization state of carbon atoms was determined by Raman spectroscopy. Analyses by infrared absorption spectroscopy were performed to investigate the O and H bonding configurations in the films produced from CO–C2H2 mixtures containing 25–75% CO. The effect of the CO concentration in the gas discharge on the characteristics of a-C:H films was analyzed and discussed in this paper.