Growth Mechanism of Oxygen-Containing Functional Plasma Polymers

Regarding the recent debate on the usefulness of macroscopic kinetics for plasma polymerization, we further investigated the deposition of oxygen-containing functional plasma polymers based on low pressure CO2/C2H4 RF discharges in order to find differences and transitions in the growth mechanism. A reduction in deposition rate with increasing CO2/C2H4 ratio and a drop in deposition rate at enhanced energy input have been observed. Both effects are found to be mainly related to plasma-chemical processes such as the production of film-forming species and oxidation in the gas phase. In contrast to plasma etching with non-polymerizing gases, ion-enhanced etching effects were found to play a secondary role for the deposition of oxygen-containing functional plasma polymers.