Electron energy distribution in capacitively-coupled RF discharges of inert gases

The electron energy distribution function (EEDF) is measured with a Langmuir probe in a symmetrically capacitively-coupled RF (13.56 MHz) discharges of inert gases over the gas pressure from 0.1 to 0.8 Torr with keeping the discharge current constant at 150 mA. The bulk of the EEDF are Druyvesteyn-like distribution over the measured gas pressure for Ne, Ar, Xe. The spatial dependence of EEDF is also measured in the RF Ar discharges. The bulk of the measured EEDF depends on the ambipolar potential, while the tail depends on the local electric field.