Langmuir probe and electron energy distribution function measurements of radio frequency ion source

In this work a single langmuir probe is used to investigate the low pressure radio-frequency (RF) discharge in argon. The current-voltage characteristic of the probe is used to provide the fundamental plasma parameters, including the electron temperature (Te), electron density (ne), floating potential (vf) and plasma potential (vp).The data are collected at plasma source pressure varying from 1 to 80 mtorr and the discharge powers in the range of 25-250 w. The measurements give an electron density and temperature of ne=1.8 x 1010 to 9.2 x 1011 cm-3 and Te=1.75 to 4.5 eV, respectively. The electron energy distribution function (EEDF) and some elementary processes involved in the RF gas discharge is deduced. The influence of the RF power and plasma cell pressure on ne,Te and vp of the plasma has been examined. The evaluation of the EEDF and its behavior with the pressure in the plasma source is also revealed.