Kinetics of formation of sulfur dimers in pure SF6 and SF6-O2 discharges

Abstract

The emission band spectra of S, molecule (B3ζu− → X3ζg− transition) and of SO molecule (A3π→ X3ζ−) were detected in SF6 and SF6-O2 rf discharges. It has been observed that the presence of a material which can be etched by SF6 products considerably enhances the density of S2 in the reactor. By means of mass spectrometry it has been shown that the m/e =83 mu signal assigned to S2F4 ions evolves exactly in the same manner as the S2 band intensity during the etching of Si or W in SF6-O2 discharge. A reaction scheme involving S2F radicals is proposed to explain these experimental results.