Self-consistent particle simulation of radio-frequency CF4 discharge with implementation of all ion–neutral reactive collisions

Abstract

The structures of the CF4 radio-frequency discharge between parallel electrodes are clarified by the use of the particle-in-cell/Monte Carlo method. The simulation is performed based on the most reliable collision data, i.e., detailed cross-section data for electron–CF4 collision, measured rate for positive–negative ion recombination, and the newly developed ion–CF4 collision model for endothermic reactions. Reactive collisions between positive ions (especially CF3+) and CF4 molecules are found to be important. The major loss process of negative ions is the recombination with positive ions. It is also found that the discharge sustaining mechanism is the ionization, not the electron detachment from negative ions.

Slope and amplitude asymmetry effects on low frequency capacitively coupled carbon tetrafluoride plasmas

“…Although more species may be present, it has been shown in previous studies that these are the dominant ones. [27][28][29][30][31][32][33] The energy-dependent cross sections for the electron-CF 4 collision processes are presented in Fig. 2(a).…”

“…2(a). The cross-sections are taken from Kurihara et al, 34 except for electron attachment processes which are taken from Bonham et al 35 A complete list of the electron impact collision processes used in this model can be found in Schulze et al 25 Although a large number of ion-CF 4 reactions take place in CF 4 discharges, 27,32,36 only a limited set of reactions are included here. The energy dependent cross sections for these reactions are shown in Fig.…”

Role of pressure in transport of F- ions in BF3 gas for technological applications

“…According to Nanbu's theory elastic and reactive endothermic collision are separated and treated by accounting for thermodynamic threshold energy and branching ratio according to the Rice-RampspergerKassel (RRK) theory [14]. Within the RRK theory excited molecular complex is treated as excited activated complex where internal energy is distributed among s equivalent oscillators-vibrational modes of the complex.…”

“…In this work instead of very often cited Langevin's theory to determine effective cross section for collision and reaction rate we used Nanbu's theory [14,15] that may succesfully distinguish between reactive and nonreactive collisions of collision partners.…”

“…The cross sections for scattering of F -ions on several molecules are calculated by using Nanbu's theory [14,15,16]. According to Nanbu's theory elastic and reactive endothermic collision are separated and treated by accounting for thermodynamic threshold energy and branching ratio according to the Rice-RampspergerKassel (RRK) theory [14].…”