Improvements on the local order of amorphous hydrogenated silicon carbide films

This paper reports improvements on the chemical and structural order of amorphous hydrogenated silicon carbide thin films, deposited by plasma enhanced chemical vapor deposition (PEVCD) at the `starving plasma regimeʹ, from a gaseous mixture of silane, methane and hydrogen. Two deposition parameters: (i) the radio frequency (rf) power and (ii) the hydrogen dilution of the gaseous mixture were analyzed. The samples were characterized by Rutherford backscattering (RBS) to obtain the filmʹs composition, by Fourier transform infrared spectrometry (FTIR) to analyze the chemical bonds in the solid phase and by means of X-ray absorption spectroscopies (XAS) to determine the short range order around the silicon atoms. The results pointed towards the use of higher rf power (>50 W) and a gaseous mixture highly diluted in H2 (a maximum H2 flow of 400 standard cubic centimeter per minute (sccm) was used) as a route to achieve films with suitable properties. The best results are accomplished in films with a carbon content close to 50%.