Comparison of microwave and lower frequency discharges for plasma polymerization

Abstract

A plasma sustained by electromagnetic surface waves (SW’s) has been used to study the deposition rate R of hydrocarbon and fluorocarbon plasma polymer films as a function of the applied field frequency f in the range 12–400 MHz. The SW technique allows one to vary only f while keeping constant all other parameters known to influence R, for example, power density P in the plasma. A plot of R/P at a total pressure of 200 mTorr (27 Pa) displays two plateaus, that at f<30 MHz being about five times lower than that at f>100 MHz. This is attributed to the fact that electron energy distribution functions differ fundamentally at radio and microwave frequencies, for the gas pressure range considered.

Travelling-wave-sustained discharges

“…Many possibilities for the use of TWSDs for surface processing and film deposition [12,149,[194][195][196][197][198][199][200][201][202][203][204][205][206][207][208][209][210][211][212][213], gas detoxification [214][215][216][217], for sterilization [218], for light sources [219][220][221][222][223] and lasers [224][225][226], for panel displays [227], for particle sources [228][229][230][231][232][233][234][235][236][237][238][239], for elementary analysis through atomic spectroscopy …”

Plasma Polymerization of Fluorocarbons

“…3). Claude et al [18][19][20] and Wertheimer et al [21] have studied the difference between these discharges and the rf ones; these authors have set up a system connected to an electromagnetic surface wave (SW) generator in order to investigate the effect of frequency changes on the deposition processes keeping constant all the other parameters. Claude et al [18][19][20] and Wertheimer et al [21] have studied the difference between these discharges and the rf ones; these authors have set up a system connected to an electromagnetic surface wave (SW) generator in order to investigate the effect of frequency changes on the deposition processes keeping constant all the other parameters.…”

An Introduction to Plasma Polymerization

“…The study of the effect of higher frequencies (radio frequency to micro wave) on plasma polymerization [99][100][101] has been addressed in a systematic fashion fairly recently. The microwave apparatus used generates a plasma of fairly even intensity over a large area, as required for deposition of uniform thin films.…”

“…9), in which a relatively larger population of electrons is found in the high energy tail for microwave frequencies than for rf [99][100][101][102]. 9), in which a relatively larger population of electrons is found in the high energy tail for microwave frequencies than for rf [99][100][101][102].…”