Pressure Dependences of Electron Energy Distribution and Power Dissipation in Symmetrical RF Discharges of Inert Gases

The plasma parameters, including the electron energy distribution function (EEDF), are measured with a Langmuir probe in symmetrically capacitively coupled RF (13.56 MHz) discharges of Ne, Ar and Xe over a range of gas pressures from 0.1 to 0.8 Torr, while keeping the RF current constant at 150 mA. The EEDFs are Druyvesteyn-like for these discharges. The average electron energy decreases with the gas pressure and the electron density increases. In bulk plasmas of respective gases, joule heating is more dominant than stochastic heating and heating due to ion acceleration, except for low-pressure Ne discharges.