We investigate the effect of external electron beam injection on plasma kinetics of a radio‐frequency (rf) capacitive argon discharge at a pressure of 100 mTorr. The rf voltage is applied to the one electrode. Monoenergetic electron beam is injected from the other electrode, with a laboratory accessible injection current and energy. The electron beam injected electrode is grounded. A direct‐implicit particle‐in‐cell/Monte‐Carlo method is used to self‐consistently simulate the plasma density, electron temperature, plasma potential, electron energy probability function (EEPF), and the electron and ion fluxes. The presence of the electron beam increases the plasma density, while decreases the electron temperature and the plasma potential. The plasma density can increase by a factor of 5, at the same time the electron temperature can decrease from 3 to 0.5 eV. The reason is that, with the electron injection, there are more low‐energy electrons occupation in the EEPF. The EEPF is sensitive to the beam modulation: even a small beam current of 0.01A can modify the EEPF significantly. This may have crucial importance for plasma processing of polymers and graphene, where low energy treatment is desired. In addition, electron and ion fluxes to the ground electrode, are also significantly modified with increasing flux and decreasing bombardment energy.

Electron-beam-sustained plasmas are of vital importance for separately controlling ion flux and ion energy. In this paper, we use an implicit particle-in-cell Monte Carlo method to study plasma kinetics in an electron-beam-sustained plasma under operating conditions relevant to the use of such plasmas for polymer processing. The results indicate that the electron and ion densities are uniformly distributed because of the uniform ionization rate and heating rate. The electron-energy distribution function is Druyvesteyn-like with an ultrahigh concentration of low-energy electrons and a high-energy tail. Low-energy electrons are beneficial for protecting the substrate in material processing and a high-energy tail is useful for the precise control of plasma-gas chemistry. For ion-energy distribution functions at the electrode surface, the low-energy (<5 eV) ion occupation rate increases with decreasing beam current or beam energy. The proportion of low-energy ions bombarding the electrode exceeds 99%, which indicates the superiority of electron-beam-generated plasma compared with a voltage- or current-driven discharge to obtain independent control of ion flux and ion energy. The results obtained herein are important for nondestructive etching in plasma processing because of the unique plasma characteristics provided by electron-beam injection.