Microstructural and chemical evolution of -C H3 -incorporated (Low- k) SiCO(H) films prepared by dielectric barrier discharge plasma

The present work focuses on the incorporation of -C H3 radicals in organic SiCO(H) films with low dielectric constant (k=2.46). The SiCO(H) films were deposited by dielectric barrier discharge plasma method using a mixture of C H4 and Ar gases at different conditions (varying the frequency and pressure). The evolution of the film microstructure was investigated by means of X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) absorption spectroscopy, and atomic force microscopy (AFM). Various bonds, C-C, C-O, Si-O, and Si-C H3, were observed in XPS. In XPS analysis, it is observed that at higher frequency range (from 1 to 5 kHz), -C H3 radicals (in the form of Si-C H3) increase significantly. FTIR absorption spectra consist of several vibrational bands: namely, Si-O-Si asymmetric stretching at 1034 cm-1, symmetric deformation of the -C H3 group in Si-C H3 configuration at 1270 cm-1, C-H stretching of -C Hx (x=2 and 3) groups in the region between 3050 and 2750 cm-1, and -OH related vibrational bands in the range between 3700 and 3150 cm-1. The change in various deposition parameters causes the change in different Si-O-Si vibrational band ratio, and the intensity of C- Hx and Si-C Hx. The film roughness was verified by AFM measurement.