Investigation of Control of Water Contact Angle by Composition Control of SiCOxHy Film Formed on Si Substrate

With the recent breakthrough in microfabrication technology, microdevices in analytical chemistry have made remarkable progress and are now being put to practical use as micro chemical analysis systems such as micro-total analysis systems (μTAS) and Lab on a Chip. In microfluidic channels, which are an elemental function of these systems, it is necessary to make the channel walls partially hydrophilic or hydrophobic for solution control, but it has been difficult to obtain a continuous and spatially stable contact angle surface. In this study, hydrogen-containing silicon carbide films were deposited on silicon under various conditions using a sputtering deposition system, a newly developed (Shinko Seiki) PIG (Penning Ionization Gauge) plasma CVD method, in order to control the contact angle. This equipment can be applied to hot cathode Penning Ionization Gauge ion source, which can easily obtain high-density plasma for plasma CVD to produce thin films. The surface structures of these films were analyzed by photoelectron spectroscopy using synchrotron radiation to control the composition of the hydrogen-containing silicon carbide oxide films. As a result, hydrophilicity of the surface was obtained with increasing oxygen flow rate in the deposition. This result is important in that it can be used for channel walls of microdevices to obtain stable contact angle surfaces and to control fluid flow.