PREPARATION OF FLUORINATED AMORPHOUS-CARBON THIN-FILMS

Fluorinated amorphous carbon (a-C:F) thin films were prepared using CH , and CF, gases by plasma chemical vapor deposition (CVD) method. The basic properties of these films were investigated by electron spin res onance (ESR), infrared (IR) absorption, optical absorption, X-ray phot oelectron spectroscopy (XPS) and dielectric constant measurements. XPS measurement revealed that the fluorine concentration of the CVD film increased to approximately 67 at.%. In one film, the CF, mode appeared in the IR spectrum and the hydrogen-related modes disappeared. The di electric constant of the film was estimated to be 2.2 at 1 MHz. The ES R spectra revealed that the carbon dangling bond density and the line width increased with increasing fluorine concentration. The increase i n the dangling bond density and the larger line width of the ESR spect rum are attributed to the larger atomic radius of fluorine compared to that of hydrogen and to the hyperfine interaction between the danglin g bonds and the fluorine nucleus, respectively. On the other hand, the g-value and the optical band gap remained unchanged with increasing f luorine concentration. This result is consistent with the fact that th e g-value is dominated by the band state. We also discuss the effect o f deposition temperature on the film properties. (C) 1998 Elsevier Sci ence B.V. All rights reserved.