Accurate Control of Surface Characteristics of Glass-like Carbon by Controlled Plasma of SF6-Ar Mixed Gas

An investigation was conducted on the formation of controlled plasma of mixed gas (SF6+Ar) and accurate control of surface characteristics of carbon material with low-damage by this plasma. We developed a method to control the plasma composition elements and the sheath voltage independently of the other plasma parameters. A controlled plasma with high ion density, low sheath voltage and designated gas-flow ratio γ, which is (flow rate of SF6) / (flow rate of SF6 +flow rate of Ar) was formed by this method. The surface of glassy carbon (GC) was modified by this plasma. In order to estimate effects of the surface modification, the contact angle of water to the glassy carbon surface and ESCA spectra before and after plasma surface modification were measured. To evaluate the damages to the glassy carbon surface, we observed the surface by SEM and measured Raman spectra. It was found from these results that accurate and wide-range control of surface characteristics of carbon materials with low-damage can be carried out by using the controlled plasma of mixed gas of (SF6 +Ar) with high ion density and moderately low sheath voltage.