A Simple Model for Ion Flux-Energy Distribution Functions in Capacitively Coupled Radio-Frequency Plasmas Driven by Arbitrary Voltage Waveforms

摘要

The ion flux-energy distribution function (IFEDF) is of crucial importance for surface processing applications of capacitively coupled radio-frequency (CCRF) plasmas. Here, we propose a model that allows for the determination of the IFEDF in such plasmas for various gases and pressures in both symmetric and asymmetric configurations. A simplified ion density profile and a quadratic charge voltage relation for the plasma sheaths are assumed in the model, of which the performance is evaluated for single-as well as multi-frequency voltage waveforms. The IFEDFs predicted by this model are compared to those obtained from PIC/MCC simulations and retarding field energy analyzer measurements. Furthermore, the development of the IFEDF shape and the ion dynamics in the plasma sheath region are discussed in detail based on the spatially and temporally resolved model data.