Dynamics of Plasma in a Dual-Frequency Capacitive Discharge in an Ar/Xe Mixture

The spatio-temporal dynamics of plasma in a symmetrical dual-frequency 81 MHz/1.76 MHz capacitive discharge under the influence of a low-frequency 1.76 MHz field has been studied. Using phase-resolved optical emission spectroscopy, the dynamics of argon and xenon emission intensity in the plasma was obtained. Measurements of the electron energy probability function (EEPF) at the center of the discharge were performed using a Langmuir probe, and electron density measurements were made using a hairpin probe. The main result is the dynamics of the intensity ratios of selected argon and xenon lines under different conditions: at pressures of 40, 200, and 400 mTorr, low-frequency voltage amplitudes of 100, 200, and 400 V, and input power at 81 MHz of 3 and 15 W. The dynamics of high-energy electrons was investigated based on a two-temperature approximation of the electron energy probability function.