Modeling of wave driven molecular (H/sub 2/, N/sub 2/, N/sub 2/-Ar) discharges as atomic sources

Microwave H/sub 2/, N/sub 2/, and N/sub 2/-Ar discharges driven by traveling surface waves are investigated as sources of ground state N(/sup 4/S), H(1s) atoms. The dissociation kinetics is discussed in the framework of theoretical models based on a self-consistent treatment of the main discharge balances, wave electrodynamics and plasma-wall interactions. It is shown that the number density of hydrogen H(1s) atoms depends heavily on the wall conditions at low pressure conditions. The kinetics of N(/sup 4/S) and metastable N(/sup 2/D) and N(/sup 2/P) atoms and of the molecular N/sub 2/(A/sup 3/(sigma)/sub u//sup +/) metastable state in a pure N/sub 2/ discharge are shown to be strongly coupled. One possible way to control and to enhance nitrogen dissociation is the use of an N/sub 2/-Ar mixture. The increase in dissociation degree of N/sub 2/ molecules at high Ar fractional concentration can be attributed to dissociative recombination between electrons and N/sub 2//sup +/ positive ions. The predicted results for the atomic density are compared with emission spectroscopy data.