A one-dimensional fluid model for an acetylene RF discharge: A study of the plasma chemistry

A one-dimensional (1-D) fluid model is developed for an RF acetylene discharge. In total, 24 species (neutrals, radicals, electrons, and ions) are considered. For every species, a mass balance equation is solved. Further, the electron energy equation and the Poisson equation fire also considered. Reactions taken into account include 19 electron-neutral, one ion-neutral, and 17 neutral-neutral reactions. The reaction rate coefficients of the ion-neutral and neutral-neutral reactions are taken from literature. The rate coefficients of the electron-neutral reactions depend strongly on the average electron energy, and are, therefore, obtained from a simplified Boltzmann equation. The 1-D fluid model yields, among others, I in. formation about the densities of the different species in the plasma. The most important neutral species in an acetylene plasma are C2H2 and H-2. Further, the radicals C4H2, C6H2, and C8H2 (to a minor extent) are also present at high densities. These higher order carbon radicals are mainly formed in neutral-neutral reactions. with C2H. Other radical species present at high, densities are H, C2H3, CH2, and CxH (with x equal to 2,4, and 6). The most important ionic species are found to be C4H2+, C2H2+, and C6H2+. Finally, a comparison is made between an acetylene and a methane plasma.