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

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. (C) 1998 American Vacuum Society. [S0734-2101(98)08103-2].