Numerical characterization of capacitively coupled CF₄ plasmas modulated by anion beam injection

Abstract

In the study of electronegative CF4 capacitively coupled plasmas (CCP), plasma modulation is typically achieved by varying parameters such as pressure and voltage, et al. In this work, the particle-in-cell/Monte Carlo (PIC/MC) method is used to simulate modulation of CF4 CCP with injection of anions (F-) ion beam (FB). The results demonstrate that FB injection effectively enhances the dissociation collision process between F- ions and neutral molecules, thus altering the densities of electrons and ions. An effective modulation of the characteristic parameters of the plasma of CF4 can be achieved by controlling the current and energy of FB. Particularly noteworthy is the transition of the heating mode from the DA mode to the dissociation mode as the FB current increases to 0.038 A (energy fixed at 10 keV) or when the FB energy exceeds 10 keV (current fixed on 0.038 A). This transition is attributed to the generation of a substantial number of electrons through dissociative collisions. This approach provides insight into the controlled modulation of plasma characteristics in CF4 CCP, offering potential applications in various plasma-based technologies.