Preparation of Carbon Thin Films by CVD Method of Organic Compounds with Low Molecular Weight and Their Electrical Propertie

Abstract

Carbon thin films on the surface of quartz substrates were prepared by the thermal decomposition of organiccompounds with low molecular weight, such as benzene, cyclohexane, tetrahydrofuran and pyridine. The structure andelectrical properties of the films obtained were studied. From SEM observations, it was found that the thickness of thecarbon films increased with the increase of the deposition time. The homogeneous films without any cracks and withoutany peeling off from the substrates were obtained with a thickness less than 1 μm. By the XRD measurements of the filmson the substrate, it was clarified that the graphitization degree of these films had very low. In order to examine thechemical bonding state in the carbon films, X-ray photoelectron spectroscopy was carried out in all films obtained. Inthe case of the film prepared from pridine, the nitrogen existed as a tertiary bonding state, replacing carbon atoms inhexagonal layers. The electrical conductivity of the film obtained from cyclohexane showed the high value of 2.5 × 105S/m, but that of the film prepared from benzene gave a small value of 0.3 × 105 S/m. Hall coefficient was found to showextremely small values at room temperature in all films obtained, ranging from 2.3 × 10-9 to-2.4 × 10-9 m3/C.