UV photon assist ionization for low temperature plasma

A new type plasma source has been developed for the generation of low temperature plasma. The plasma generation process consists of two steps, the generation of metastable neutral gas by injecting a low energy electron beam (the thermionic source) and the ionization of the metastable neutral gas by application of a UV light source. The key characteristic of this plasma source is the capability of producing extremely low temperature plasma.In the experiment, the filament heating current is 6.5 A and the electron acceleration voltage varies from 16 V to 25 V. Plasma parameters are measured by a single Langmuir probe. The plasma density increases 100%, from 4.5 × 109 cm−3 to 9.8 × 109 cm−3 in Ar 30 mTorr when the neutrals excited by the e-beam are exposed to the UV light. However, the electron temperature is still low, i.e., ∼0.5 eV. A similar result is observed in the case of Xe.