Applications of dielectric barrier discharges

Dielectric barrier discharges (DBDs) in oxygen and air are well established for the production of large quantities of ozone and are more recently being applied to a wider range of plasmachemical processes. Here, the application of DBDs for ozone synthesis, the non-thermal oxidation of volatile organic compounds (VOCs) in air, the generation of incoherent (V)UV radiation and surface processing (etching, ashing) is presented. The main plasmaphysical features of sinusoidally-driven DBDs (transient, filamented, non-thermal plasmas at atmospheric pressure) are described, and a simple plasmachemical reaction pathway for ozone synthesis are give. Experimental results on the degradation of VOCs (2-propanol, trichloroethylene, carbon tetrachloride), as well as byproduct formation is presented for stand-alone DBD treatment, as well as for simultaneous (V)UV illumination of the discharge. Illumination of the discharge with (V)UV can change the plasmachemistry by enhanced formation of certain species of radicals--and thereby change byproduct formation--but also can change the discharge physics, known as the Joshi effect. As an example for generation of excited dimers and exiplexes for the production of incoherent UV light, experimental results on a XeBr* excimer UV light source are presented. Effects of the total and partial pressure of a Xe/Br{sub 2} system, the gap spacing and the applied driving frequency on the UV radiant efficiency are shown. For the application of DBDs for surface processing, experimental results of photoresist ashing on Si wafers using DBDs in oxygen are shown function of gas pressure, gap spacing and applied frequency