Measurements of plasma parameters in capacitively coupled radio frequency plasma from discharge characteristics: Correlation with optical emission spectroscopy

• A capacitively coupled radio frequency plasma has been investigated.
• The electrical discharge characteristics are used to calculate the plasma parameters.
• The modified homogeneous discharge model is incorporated in the technique.
• Irregular variation of plasma density with operating pressure is observed.
• Irregular variation of plasma density is reconfirmed by optical emission spectroscopy.

Plasma parameters from the discharge characteristics of a 13.56 MHz capacitively coupled radio frequency Ar plasma are evaluated on the basis of homogeneous discharge model for wide range of operating pressure. The homogeneous discharge model of capacitively coupled radio frequency discharge is modified to take into account the nonlinear plasma series resonance effect. The effect of drift velocity of the electron due to change in radio frequency electric field and operating pressure is also considered. Considerable dependent of plasma parameters on the drift velocity of the electron as well as on the plasma series resonance effect are observed in low pressure. An irregular variation of calculated plasma density with operating pressure is observed, which is reconfirmed with optical emission spectroscopy.