Experimental Investigations on Ne/CF4 Inductively Coupled Discharges

A Langmuir probe measurement was applied to an inductively-coupled RF (13.56 MHz) Ne/CF4 discharge over a pressure range from 20 mTorr to 60 mTorr while changing the CF4 content from 5 to 20%, and keeping the power injected into the plasma at about 100 W. The measured electron energy distribution function (EEDF) under any condition deviated from the Maxwellian distribution in the energy region higher than the lowest excitation threshold energy of Ne. The average electron energy, electron density and dissociation rate coefficient estimated using the measured EEDF decreased slightly with increasing CF4 content. The EEDF and the dissociation rate coefficient in Ar/CF4 and Ne/CF4 discharges under an equally injected power were compared. The number of electrons with energy higher than the dissociation threshold energy in Ne/CF4 were much larger than that in Ar/CF4, yielding a difference in dissociation rate coefficient of one order of magnitude.