Investigation of Material Properties of Fluorocarbon Films Deposited by Plasma-Enhanced Chemical Vapor Deposition

Energy-related research at phase boundaries has attracted much attention in recent years. In particular, the boundary between electronic materials and liquid water is interesting from application viewpoints. Since the potential gradient of the liquid phase are affected by the properties of solid materials, controlling the properties of solid materials in the presence of liquid is an important factor in improving their output performance of application. In this study, we focused on polar fluorocarbon films and investigated their physical properties. C4F8 molecule was used as a precursor gas to deposit film by plasma-enhanced chemical vapor deposition. We investigated the effect of deposition pressure on bonding state formation and physical properties of the films. Composition ratio of the film is changed to fluorine rich at high pressure that is confirmed by x-ray photoelectron spectroscopy. It is considered that the dissociation of precursor in the plasma and polymerization reactions on the substrate affect the film composition. Similarly, the surface resistivity is decreased, and the zeta potential changed to negative value. This is due to reduction of sp2 carbon which contributes conductivity at high pressure. Thus, composition ratio of bond state can be controlled by discharge condition. These results are considered useful to maximize output performance of the devices at phase interface.