Plasma polymerization using pulsed microwave power

Pulsed microwave power was used to polymerize a variety of monomers containing different functional groups. We examined the effects of pulse frequency and duty cycle on the deposition rates and the composition of the polymers. For monomers that do not contain oxygen we find that there is an increase in deposition rate with increasing pulse frequency and that the pulsed deposition rate is always less than the continuous power deposition rate. For monomers that contain oxygen, or for co-depositions of hydrocarbon monomers with O₂ or CO, we find that there is a decrease in deposition rate with increasing frequency, however the deposition rate using pulsed power is greater than the rate using continuous power. This result is shown to be related to the amount of etching that takes place during the deposition process. Infrared studies reveal that pulsed power can alter the composition of plasma polymers of some oxygen-containing monomers. The presence or absence of vinyl unsaturation, nitrile groups, or a cyclic structure have no effect on the polymerization process.