Numerical simulation of capacitively coupled plasma driven by tailored voltage waveforms with electron beam injection modulation

In this study, a one-dimensional particle-in-cell/Monte Carlo collision model was employed to simulate capacitively coupled plasma discharges driven by tailored voltage waveforms and modulated with electron beam (EB) injection. The electrical asymmetry introduced by tailored voltage waveform leads to distinct plasma behaviors depending on the EB injection side. The effects of injection location, EB current, and electron energy on plasma characteristics were systematically investigated. Injection from the powered electrode significantly enhances plasma density and produces striped ionization structures in the sheath, resulting from the combined effects of the ionization energy threshold and sheath acceleration. As the electron energy increases, injection from the grounded side becomes more effective, eventually yielding higher densities due to longer electron trajectories and enhanced ionization. Increasing the EB current density from 0.5 to 2.0 A/m2 results in more uniform ionization in the bulk while maintaining an expanded but stable sheath. Moreover, the maximum ion energy at the grounded electrode decreases with increasing EB current, offering potential for ion energy control in plasma processing.