抄録
Deposition of plasma-polymerized ethylene film on a glass substrate loaded in a bell-jar type plasma apparatus was examined by varying plasma parameters such as high frequency power, monomer flow rate, and location of the substrate. Variation of high frequency power resulted in a fairly small change of the deposition rate of the polymer film, presumably because of an external electrode system employed for plasma break down of argon entering from the upper side of the bell jar. Effective transparency of the film having 10000 Å thickness was obtained throughout the visible light range while enhanced light absorbance was observed with shorter wavelengths in the ultraviolet range so that it is possible to estimate the film thickness by simply measuring absorbance of the polymer deposited on a quartz glass slide at 300 nm. An increase of ethylene flow rate resulted in higher deposition rate, but an abrupt drop in the deposition rate was experienced under flow rate exceeding a certain limit, while and adhesion of powder material was observed at the same time. Varying height of the sample stand on which the substrate was placed also affected the deposition rate but the optimum height could be found from the uniform film thickness throughout the surface of the glass slide. Deposition rate at various locations other than on the sample stand also differed greatly but a gas chromatographic study revealed a considerably uniform ethylene concentration within the bell jar so that it was assumed that the mode of polymer deposition in a given apparatus was mainly derived from the gas discharge condition at the surface of the substrate.
