Study of attachment-detachment instabilities in RF and DC discharges using the SIGLO one-dimensional codes
- Universite Paul Sabatier, Toulouse (France)
- Kinema Research, Monument Colorado, CO (United States)
The purpose of this communication is to present a 1-D fluid model of DC and RF discharges in 1-D and to show examples of results from this model in electronegative gases under conditions where the attachment-detachment-ionization instability appears in the body of the plasma. The codes corresponding to these models are referred to as belonging to the SIGLO (Simulation of GLOw discharges) series. The physical and numerical models have been formulated for especially rapid computation on a PC. The rapid computational times make this model suitable for parametric studies and the incorporation of on-line graphics (such as movies showing the evolution of the charged particle densities and electric field distributions) directly into the computer model. The results we present here are in CF4 for DC and RF (13.56 Mhz) applied voltages, for a pressure of 1 torr and a gap length of 4 cm. The conditions are close to those of Gogolides et al., and we illustrate here the possibility of attachment induced instabilities when detachment is significant. Detachment of the fluorine negative ion F- by CFP{sub x} radicals could be efficient in CF{sub 4} plasmas. In this paper we consider the detachment frequency due to CF{sub x} radicals as a parameters and study the structure and evolution of the discharge in the presence of attachment-detachment instabilities. The results show that for some values of the detachment frequency, the charged particle densities and field amplitude in the plasma of a RF discharge in CF{sub 4} do not reach constant (time independent) values but oscillates, at a frequency much lower than the applied voltage (typically on the order of 10 kHz in our conditions). The plasma column contains adjacent low field and strong field {open_quotes}domains{close_quotes} where the relative concentrations of electrons and negative ions are different.
- OSTI ID:
- 213025
- Report Number(s):
- CONF-950749--
- Country of Publication:
- United States
- Language:
- English
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