Numerical simulation of discharge mode in capacitively coupled plasma with beam injection*

In recent years, the capacitively coupled plasmas (CCP) is modulated by electrical asymmetry effect (EAE), magnetical asymmetry effect (MAE), electron beam (EB) injection et al. Some reports describe the energy electron provided by EB can directly take part in the ionized reaction in plasma to increase the electron density. In this work, we used 1D implicit particle-in-cell/Monte Carlo collisions (PIC/MCC) to study the modulation of CCP with the beam injection. The results indicate that the trend of electron density in DF-CCP does not always increase with EB energy (10 eV<ε<300 eV), which is due to the lower ability of the bulk plasma to capture high-energy electrons. Moreover, the asymmetric sheath could bring up different influences of gamma mode to control the self-bias voltage. When the Ar⁺ beam injects into SF-CCP, the discharge mode can be changed with the increase of ion-induced secondary electron emission coefficient γ and discharge pressure. Furthermore, the secondary electrons emitted by ions from the injected electrode increase the electron density and result in the high-energy tail of EEPF. Therefore, the IB injection could be expected to be one of the effective methods to modulate the CCP.