Electron interactions with c-C4F8

The limited electron collision cross-section and transport-coefficient data for the plasma processing gas perfluorocyclobutane (C-C4F8) are synthesize d, assessed, and discussed. These include cross sections for total electron scattering, differential elastic electron scattering, partial and total io nization, dissociation into neutral fragments, and electron attachment, as well as data on electron transport, ionization, and attachment coefficients . The available data on both the electron collision cross sections and the electron transport coefficients require confirmation. Also, measurements ar e needed of the momentum transfer and elastic integral cross sections, and of the cross sections for other. significant low-energy electron collision processes such as vibrational and electronic excitation. In addition, elect ron transport data over a wider range of values of the density-reduced elec tric held are needed. The present assessment of data on electron affinity, attachment, and scattering suggests the existence of negative ion states ne ar - 0.6, 4.9, 6.9, 9.0, and 10.5 eV. (C) 2001 by the U.S. Secretary of Com merce on behalf of the United States. AII rights reserved.