On volt-ampere characteristic of symmetric CCP

The dynamic and static volt/ampere characteristics I(V) are fundamental parameters of rf discharges. The discharge volt/ampere characteristics or impedance and their scaling laws are important for verification of discharge models and in the design of rf matching-tuning networks that couple plasma with an RF power source. It is pointed out that experiments with symmetrical capacitively coupled plasmas performed in a wide range of driving frequencies, gas types and pressures, and discharge voltages demonstrate a linear static volt-ampere characteristic. Such a behavior contradicts the widely accepted rf sheath models found in textbooks. The disagreement was shown to be due to the violation of the rf sheath charge conservation and, possibly, the neglect of ionization caused by oscillating electrons in the rf sheath models.