Kinetic model of a low-pressure microwave discharge in O-2-N-2 including the effects of O- ions on the characteristics for plasma maintenance

A consistent theoretical analysis of a low-pressure (p = 1 Torr) microwave discharge (omega/2 pi = 433 MHz and 2450 MHz) in O-2-N-2 is presented. The model is based on the coupled solutions to the homogeneous electron Boltzma nn equation and a system of rate balance equations for the dominant neutral and charged particles in the discharge. The sustaining electric field is s elf-consistently derived from the set of continuity and momentum transfer e quations for electrons and ions O-2(+), O+, NO+, N-2(+), N-4(+) and O-. A d eviation from the classical ambipolar diffusion is observed due to the pres ence of O- ions. The recombination of O(P-3) atoms on the tube walls is tak en into account through a Monte-Carlo-like simulation of a sequence of elem entary surface processes. This formulation provides results for the mean in put power absorbed from the field per electron, theta, and for the concentr ations of O-2(a (1)Delta(g)) and O(P-3) in satisfactory agreement with meas ured data. Other important calculated data such as the concentrations of th e ionic species and the percentage contributions of the various ionization mechanisms are also reported.