Fluorinated amorphous carbon thin films: Analysis of the role of the plasma source frequency on the structural and optical properties

Different types of fluorinated amorphous carbon (a-C:H:F) thin films were g rown by CH4/CF4/Ar mixtures using a 13.56 MHz radio frequency (rf) and a 13 .56 MHz rf -2.45 GHz microwave hybrid plasma source. The optical properties of films were carried out by ellipsometric measurement, while x-ray photoe lectron spectroscopy (XPS) and Raman spectroscopy were exploited to study t heir structural and vibrational properties. XPS spectra showed that the flu orine incorporation increased with the CF4 partial pressure while fluorine- poorer films were deposited with the rf-microwave hybrid technique., Raman measurements also suggested that with increasing fluorine content, the film microstructure changed from diamond-like to polymer-like.. The mechanism o f the a-C:H:F refractive index dependency on the plasma source frequency is investigated in terms of the amount of fluorine incorporation in the films produced. (C) 2001 American Vacuum Society.