Yasushi Sawada

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

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.

The reduction of copper oxide thin films with hydrogen plasma generated by an atmospheric-pressure glow discharge

The reduction of copper oxide thin films by a hydrogen plasma generated by an atmospheric-pressure glow (APG) discharge was investigated. The copper oxide films were prepared by heating the sputtered copper films to C in the air (heat-formed copper oxide) or by sputtering (sputtered copper oxide). Both films were composed of . The reduction occurs first on the surface, then the interface gradually shifts from the surface into the inner region and finally the whole layer is reduced to metallic copper. This process is approximately explained by assuming that the diffusion of the atomic hydrogen in the reduced layer is the rate-deyermining step. By transmission electron microscopic (TEM) observation, a layer of 3 - 5 nm thickness composed of many microcrystals was observed along the surface of the heat-formed copper oxide. After the APG hydrogen plasma treatment, the crystal layer disappeared and the crystalline lattice was re-arranged to form large crystal Cu grains.