Comparison of experimental measurements and model predictions for radio-frequency Ar and SF6 discharges

Abstract

Using a continuum model based on dc field data, the discharge physics of Ar and SF6 has been simulated for 13.5-MHz excitation. In Ar, the ionization primarily occurs at the bulk–sheath interfaces and is temporally modulated with its maximum corresponding to the cathodic phase of the rf cycle. In SF6, the ionization is distributed throughout the bulk with a maximum occurring at the bulk–sheath interface and a temporal maximum occurring during the anodic phase. The plasma induced emission (PIE), which correlates with the predicted ionization rate, has been experimentally measured as a function of position and time and agrees well with the model predictions. These results explain the phase shift of the PIE between electronegative and electropositive discharges.