Investigation On Preparation,Structure And Dielectric Properties Of Amorphous Fluorinated Carbon Films

Amorphous fluorinated carbon (a.-C:F) films with F/C ratios between 0.11 and 0.62 are prepared by microwave electron cyclotron resonance (ECR) plasma chemical vapor deposition (CVD) using trifluromethane (Ct-if3) and benzene (C6H6) as source gases. The work is focused on preparation of films, microwave discharge, bonding configurations and dielectric property of o~-C:F films.By film thickness measured, Fourier transformed infrared spectrometer (FTIR) analysis, x-ray photoelectron spectroscopy (XPS) analysis and relative irradiance measurement, the effect of microwave input powers on deposition rates, F/C ratios, bonding configurations of ct-C:F films and the radicals in plasma originating from source gases dissociation is analyzed. It shows that the increasing of microwave power can result in increasing of deposition rate, but decreasing of F/C ratios and abundance of CF and CF3 groups in cL-C:F films, and keeping that of CF2 group variation around a constant. It finds that the radicals generated in plasma control the deposition process and the main bonding configurations of films are dependent on the ratio of CF and CF2 radicals in films. The films composed of CF2 and CC bonds can be obtained at microwave power above 560 W.The frequency dependence of dielectric constant ~ (f 1 x 10~? x 106 LIz)IIand dielectric loss tan5 (f = lxi 02 ?1 x 1 O5Hz) follow a power law respectively and all show decreasing trends as frequency raised. By comparison of dielectric constant at low frequency with that at optical frequency, it proves that the dielectric polarization of a-C:F films mainly comes from the electron polarization.Ye ChaoDirected by Ning Zhaoyuan...