Incorporation of Si in a-C:Si:H films monitored by infrared excited Raman scattering

Silicon-containing diamond-like amorphous carbon layers with varying Si content were prepared from methane and tetramethylsilane gas mixture by plasma enhanced CVD. The bonding configuration of the samples was examined by XPS and Raman spectroscopy. By the decomposition of scattering spectra excited by the 488 nm line of an Ar ion laser, it was found that, besides the well-known shift of the G peak to lower wavenumbers with increasing Si content, there is still a contribution to the scattered intensity in the 1550–1600 cm − 1 region even in the spectrum of sample with highest Si content studied. By using near-infrared (785 nm) laser for the Raman probe, we prove the presence of a distinguishable band in the G peak region. Our Raman results show the preservation of sp 2 clusters without any Si incorporation in a-C:Si:H films.