Synthesis of plasma-polymerized tetraethoxysilane and hexamethyldisiloxane films prepared by atmospheric pressure glow discharge

Abstract

The synthesis of plasma-polymerized tetraethoxysilane (TEOS) and hexamethyldisiloxane (HMDSO) thin films by atmospheric pressure glow (APG) discharge was investigated and the characteristics of this method were compared with those of low-pressure plasma-enhanced CVD (LPPECVD) methods. The obtained films had smooth surfaces, no pinholes and uniform thicknesses. The qualities of the films analysed by FTIR and XPS, and emission spectra during the reaction, were very similar to those observed in the LPPECVD. The relationship between the substrate temperature and the deposition rate was strongly dependent on the presence of oxygen; the deposition rate increased with increases in the substrate temperature in the presence of oxygen. This behaviour is uniquely characteristic of the APG discharge process. This is because the gas-phase reaction of the monomer decompositions is enhanced by atomic oxygen, and the reaction rates in the gas phase increase as the gas-phase temperature increases.