Sheath voltage ratio for asymmetric RF discharges

Summary form only given. Spherical and cylindrical many-particle models are being used to simulate RF discharges in which the RF powered and the grounded electrodes have different areas. This asymmetry determines the magnitude of the self-bias voltage V_a (the ion bombarding energy) at the powered electrode, which is a critical process parameter. One-dimensional (radial) spherical shell models have been developed, incorporating various assumptions for the sheath and the glow discharges, leading to a scaling which is in agreement with some measurements. The spherical model has been simulated with a nonuniform ionization, and the results agree with the theory. The cylindrical simulation shows that the floating potential plays an important role. The simulation results were obtained graphically as the sheath voltage ratio versus area ratio. The simulation codes are PDC1 (cylindrical) and PDS1 (spherical), which utilize particle-in-cell techniques plus Monte Carlo simulation of electron-neutral and ion-neutral collisions