Assessed Total and Partial Ionization Cross Sections for CF4, C2F6, C3F8, CHF3, CF3I, c-C4F8, Cl2, CCl2F2, BCl3, SF6, and Fragments of CF4 and SF6

Abstract

We have recently completed an updated review, synthesis, assessment, and discussion of low-energy electron interactions with the plasma processing gases CF4, C2F6, C3F8, CHF3, CF3I, c-C4F8, Cl2, CCl2F2, BCl3, SF6. This work, along with fundamental knowledge on electron-molecule collision processes, the definition of the various electron collision cross sections and rate coefficients, and the experimental and theoretical methods used for their determination have been described in Christophorou and Olthoff.1 It has been shown in this reference, that reliable data on the electron transport, electron attachment, and electron-impact ionization coefficients generally exist for most of these molecules, except for electron transport in strongly electronegative gases. Also, reliable data exist on the collision cross sections for most of these molecules, but this knowledge depends on the collision process and the molecule under consideration. The cross sections and coefficients that have been recommended or suggested1 were based on experimental measurements. This work1 has shown that while a great deal of quantitative data have become available, especially recently, for the molecules under consideration, there is still a pressing need for quantitative measurements of the cross sections for electron-impact dissociation into neutral fragments, direct and indirect vibrational (and electronic) excitation, and electron interaction processes involving excited and transient (radical) species.