Parameters and Composition of Plasma in a Mixture of CF4 + H2 + Ar: Effect of the CF4/H2 Ratio

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Abstract

A study of the electrophysical parameters of plasma and the kinetics of plasma-chemical processes in CF4 + H2 + Ar mixture by varying the CF4/H2 ratio were carried out. Using diagnostic methods and plasma modeling together, it was found that replacing tetrafluoromethane with hydrogen a) leads to a decrease in plasma density and an increase in electronegativity; and b) causes a disproportionately sharp drop in the concentration of fluorine atoms. The reason for the latter effect is an increase in the frequency of death of atoms in reactions of the form CHFx + F → CFx + HF, initiated by heterogeneous recombination according to the CFx + H → CHFx mechanism. A simultaneous increase in the concentration of polymer-forming radicals CHxFy (x + y < 3) indicates an increase in the polymerization load of the plasma on the surfaces in contact with it.

About the authors

A. V. Miakonkikh

Valiev Institute of Physics and Technology of Russian Academy of Sciences

Author for correspondence.
Email: miakonkikh@ftian.ru
Russian Federation, Moscow

V. O. Kuzmenko

Valiev Institute of Physics and Technology of Russian Academy of Sciences

Email: miakonkikh@ftian.ru
Russian Federation, Moscow

A. M. Efremov

Ivanovo State University of Chemistry and Technology

Email: miakonkikh@ftian.ru
Russian Federation, Ivanovo

K. V. Rudenko

Valiev Institute of Physics and Technology of Russian Academy of Sciences

Email: miakonkikh@ftian.ru
Russian Federation, Moscow

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Supplementary files

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2. Fig. 1. Electrophysical parameters of the plasma in the CF4 + H2 + Ar mixture at p = 10 mtor and W = 1500 W: 1 - electron temperature; 2 - electron concentration; 3 - total concentration of positive ions; 4 - relative concentration of negative ions. Dotted lines represent the values obtained by plasma modeling

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3. Fig. 2. Concentrations of neutral particles (a) and formation rates of fluorine atoms (b) in the plasma of the CF4 + H2 + Ar mixture. The dotted lines in Fig. a show which emit hydrogen-containing particles. The conditions of plasma excitation correspond to Fig. 1

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4. Fig. 3. Radiation intensities (a) and atom concentrations (b) in the plasma of the CF4 + H2 + Ar mixture. In Fig. a: 1 - Ar 750.4 nm; 2 - F 703.4 nm; 3 - H 656.4 nm. In Fig. b: 2 - fluorine atoms; 3 - hydrogen atoms. The dotted lines in Fig. b represent the values obtained by plasma modeling

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