Nonlinear sheath motion and stochastic heating in a capacitive RF discharge

Summary form only given. Low-pressure (<100-mtorr) capacitive RF discharges are widely used in the electronics industry. It has been shown that stochastic heating by the oscillating sheaths is a major energy deposition mechanism. An analytical model of the sheath motion predicts that the heating rate is sensitively dependent on the detailed shape of the nonsinusoidal sheath motion. An experimental procedure has been developed for determining this sheath motion. A high-frequency-response Langmuir probe measures the sheath potential throughout the sheath region as a function of position and time. The probe-discharge system can be modeled as a nonlinear capacitive voltage divider. Incorporating the nonlinear sheath motion into this circuit model yields a set of equations that are solved numerically, and the resulting waveforms are compared with the experimental observations both in magnitude and harmonic content. The parameters describing the sheath motion can then be varied to match the experimentally observed potential