Rapid calculation of the ion energy distribution on a plasma electrode

A model was developed to rapidly calculate the ion energy distribution (IED) on an electrode immersed in plasma, for a given voltage waveform applied to the electrode through a blocking capacitor. The model combined an equivalent circuit representation of the system, with an equation for a damped potential to which ions respond, during their transit through the sheath. Predicted IEDs on both conducting and insulating surfaces for a variety of applied voltage waveforms (spike, staircase, square wave, etc.) agreed with published experimental data. For these comparisons with experiments, peak broadening due to the resolution of the ion energy analyzer was also taken into account. Using “tailored” waveforms of the applied voltage, desired IEDs may be obtained in terms of peak energies and fraction of ions under each peak.