ELECTRICAL CHARACTERISTICS OF PLASMA LOADED, RADIO-FREQUENCY DRIVEN, CAPACITIVELY COUPLED ELECTRODES

A simple, nonlinear circuit model of a plasma sheath was used to study impedance and harmonic generation at a radio frequency (rf) driven electrode immersed in a plasma. The impedance can be estimated from linear expressions of the conduction and displacement currents; i.e., nonlinear effects on impedance are small. Harmonic generation occurs from nonlinearities in the sheath. The harmonic level at the electrode is influenced both by the plasma parameters and the electrical circuitry attached to the electrode. Thus any use of the harmonic levels for a plasma diagnostic must take into account the stray and actual components attached to the electrode.