Spectroscopic analysis of graphitization and grain orientation of carbon films grown by photoemission-assisted plasma-enhanced chemical vapor deposition

The degrees of graphitization of carbon films grown by photoemission- assisted plasma-enhanced chemical vapor deposition were evaluated by hard-X-ray photoemission spectroscopy (HAXPES). The films were grown with a CH ₄/He or CH₄/Ar mixture at growth temperatures from 400 to 1000 °C. Low-temperature growth was mainly focused on. The result of HAXPES showed that the films dominantly have sp² bonding states. The film grown at 400 °C with CH₄/Ar had an sp² content of 84%, which was comparable to those of the films grown at temperatures ≥800 °C. The orientation of the graphitic grains was also examined by soft-X-ray absorption spectroscopy. The degrees of orientation of the films were up to 70%, compared to that of highly oriented pyrolytic graphite. The film grown at 400 °C with CH₄/Ar had the degree of graphitization of ~40%, which was comparable to that for the film grown at 800 °C with CH₄/He.