dc cathodic polymerization of trimethylsilane in a closed reactor system

dc cathodic polymerization of trimethylsilane (TMS). in a closed reactor sy stem was investigated. The composition of reactive species in the gas phase was monitored during the deposition process by a residual gas analyzer. It was found that, in such a closed plasma system, the deposition of TMS plas ma polymers could be visualized as three consecutive, time-delayed, consecu tive three fundamental processes. In the early stage of plasma deposition ( < 60 s after the initiation of plasma), the deposition of plasma polymers w as dominated by the polymerization of silicon-based species because the sil icon-based species polymerized much quicker than carbon-based species. In t he second stage of plasma deposition (between 60 and 120 s), the deposition was then dominated by carbon-based species due to the consumption of silic on in the early stage. In the final stage (more than 120 s), because of the total consumption of all the polymerizable species in the system, the depo sition stopped and the deposited plasma polymer surface was continuously tr eated by nonpolymer forming gas plasma. As a result, the TMS plasma coating s obtained under such operations have a unique chemical structure that grad ually changes from a lower carbon (C/Si ratio of similar to1.7 at the film/ substrate interface) to carbon rich (C/Si ratio of similar to4.7 on the sur face), as identified by x-ray photoelectron spectroscopy analysis. (C) 2001 American Vacuum Society.