Fluorine incorporated amorphous carbon thin films prepared by Surface Wave Microwave Plasma CVD

Abstract

Fluorine incorporated amorphous carbon (a-C:F) thin films were prepared by Microwave Surface Wave Plasma chemical vapour deposition (MW SWP CVD) using a mixture of carbon tetrafluoride (CF 4) and acetylene (C 2H 2) gas along with argon (Ar) as dilution gas. Optical properties studied by ultraviolet-visible spectroscopy shows an increase in optical band gap with respect to CF 4/C 2H 2 flow rate ratio. Fourier transforms infrared spectroscopy (FTIR) studies show formation of C–F bonding configuration with high fluorine incorporation. X-ray photoelectron spectroscopy (XPS) shows carbon peaks shifted to higher binding energy levels due to carbon fluorine linking. CF x bonding configuration enhanced with more and more fluorine incorporation. Raman studies of the films show structural transition with fluorine incorporation. From these studies correlation of optical properties, bonding configuration and structural properties of fluorinated carbon thin films were discussed.