Plasma Impedance in Discharges

摘要: Impedance is a significant parameter of glow discharges that is related to electron and ion heating, wave propagation in the plasma medium, and geometrical characteristics of the vessel used for plasma processing. We present fundamental analysis of plasma conductivity and permittivity and how these parameters can be used for the definition of plasma impedance after taking into account plasma boundaries. The discussion is focused on capacitively coupled glow discharges, and the dependence of impedance on plasma microscopic parameters is reviewed. This relation is studied for different plasma regimes, and electrical equivalent circuits of glow discharges are drawn for several process conditions. Moreover, we discuss the basic aspects of maximum power transfer theory and the necessity to match the complex plasma impedance. Guidelines for the design of matching units with the support of different …