Spectroscopic studies on preparation of silicon oxide films by PECVD using organosilicon compounds

Using methyl- and methoxy-group organosilicon compounds as gas sources, low-temperature preparation of silicon oxide thin films was performed by inductively coupled RF plasma-enhanced CVD. The chemical bonding states and compositions of deposited films were analysed both by Fourier transform infrared spectroscopy and by x-ray photoelectron spectroscopy. It has become clear that the SiO-CH3 bonds in reactant molecules are easily decomposed without oxygen even near room temperature, whereas the decomposition of Si-CH3 needs the assistance of oxygen radicals. In the deposition process the behaviour of emissive molecules and radicals in the plasmas was clarified by optical emission spectroscopy. The formation mechanism of the Si-O-Si network from methoxy-group organosilicon compounds is also discussed.