The characterization of the plasma state is of great interest in industrial applications based on plasma enhanced chemical vapour deposition (CVD) processes. We have performed experiments on a capacitively coupled radio frequency discharges in air and SF6. The use of gases containing electronegative components, such as oxygen or fluorine, leads to quite peculiar discharges, due to the presence of negative ions which affects the transport properties of such a plasma. Plasma parameters have been measured by means of movable electrostatic Langmuir probes. The implementation of a suitable numerical model of gas-phase chemistry and transport phenomena allow us to predict the amount of negative ions. In particular we show that the ion to electron density ratio strongly depends on the diffusion process and on ion recombination rates. Thus measuring it leads to a better understanding of ion diffusion and in particular of the ambipolar electric field.

Riccardi, C., Barni, R., De Colle, F., & Fontanesi, M. (2000). Characterization of electronegative plasmas. CZECHOSLOVAK JOURNAL OF PHYSICS, 50(S3), 441-444.

Characterization of electronegative plasmas

RICCARDI, CLAUDIA;BARNI, RUGGERO;FONTANESI, MARCELLO
2000

Abstract

The characterization of the plasma state is of great interest in industrial applications based on plasma enhanced chemical vapour deposition (CVD) processes. We have performed experiments on a capacitively coupled radio frequency discharges in air and SF6. The use of gases containing electronegative components, such as oxygen or fluorine, leads to quite peculiar discharges, due to the presence of negative ions which affects the transport properties of such a plasma. Plasma parameters have been measured by means of movable electrostatic Langmuir probes. The implementation of a suitable numerical model of gas-phase chemistry and transport phenomena allow us to predict the amount of negative ions. In particular we show that the ion to electron density ratio strongly depends on the diffusion process and on ion recombination rates. Thus measuring it leads to a better understanding of ion diffusion and in particular of the ambipolar electric field.
Articolo in rivista - Articolo scientifico
plasma; diagnostics;
English
441
444
Riccardi, C., Barni, R., De Colle, F., & Fontanesi, M. (2000). Characterization of electronegative plasmas. CZECHOSLOVAK JOURNAL OF PHYSICS, 50(S3), 441-444.
Riccardi, C; Barni, R; De Colle, F; Fontanesi, M
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/446
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