Spatial structure of a slot-antenna excited microwave N2–Ar plasma source

The spatial structure of a large-scale, slot-antenna excited (2.45GHz) surface wave plasma source operating in N2–Ar mixtures is investigated. A self-consistent theoretical model is developed in the local approximation to investigate the entire spatial structure of the system, including the discharge zone sustained by the field of the TM140 surface mode and the remote plasma zone. Maxwell’s equations and the rate balance equations for the most important excited species—vibrationally and electronically excited states, ions, and N(S4) atoms—and the electron Boltzmann are consistently solved. The pumping of the higher νth levels of N2(XΣg+1,ν) molecules is shown to be very effective and to strongly influence the remote plasma kinetics. Collisions of N2(XΣg+1,ν) molecules with N(S4) atoms are responsible for the increase in the number densities of electrons and electronically excited states N2(AΣu+3,BΠg3,CΠu3,a′Σu−1) in the “far” remote plasma zone.