Plasma torches for the generation of atomic fluorine and nitrogen

Summary form only given. Several microwave-driven plasma torch are being developed for a number of applications. This technology, named "MIDJet," has no electrodes or dielectric containment vessel, instead relying on a strong vortex flow to confine the discharge. This allows operation at very high power with extremely reactive gases. At 25 kW using 915 MHz microwaves, the focus has been on the generation of atomic fluorine. At a power of 23 kW it has been operated with 900 slm of helium and 25 slm of SF/sub 6/. From equilibrium calculations, this should result in 1.5/spl middot/10/sup 22/ atoms/s of atomic fluorine. This corresponds to a dissociation fraction of roughly 50%. Future tests will include operation with NF/sub 3/. This MIDJet is an extension of technology run with 5 kW at 2450 MHz. Torches at this power have been run with a variety of gases, including air, helium, oxygen and pure SF/sub 6/. Currently, torches using nitrogen and steam are under development. The nitrogen MIDJet is intended for use in a system for the generation of high fluxes of atomic nitrogen. Fluxes of 10/sup 21/ atoms/s have been produced with dissociation fractions of about 10%. The inferred temperature for this operation was about 5000 C.