Preparation of fluorinated amorphous carbon nitride films by magnetron sputtering

Fluorinated amorphous carbon nitride (a-C1-xNx:F) films were prepared by magnetron sputtering to reduce the C triple bond N bonding configuration and the dangling bond density, while increasing the optical bandgap over that of amorphous carbon nitride (a-C1-xNx) and hydrogenated amorphous carbon nitride (a-C1-xNx: H) films. The structural optical, and defect properties of these films were investigated by infrared absorption, X-ray photoelectron spectroscopy, ultraviolet-visual spectroscopy, and electron spin resonance (ESR) measurements. No IR peaks due to C triple bond N bonding were observed for the a-C1-xNx: F films, indicating that the amount of C triple N bonding decreased with the incorporation of fluorine atoms. Furthermore, IR signals due to the Raman G band were not observed in any of the films, although the Raman D band was observed for all of them. In addition, the IR spectra revealed that CF2 bonding dominated over CF bonding. These results can be explained in terms of a decrease in structural dimension owing to fluorine incorporation and a `perfect' amorphous structure that has no graphite crystalline region. The dangling bond density, peak to peak line width, g values of the ESR spectra, and optical bandgap for a-C1-xNx: F films were smaller than those for a-C : F films.