Y. Ohtsu et al., TEMPORAL BEHAVIOR OF CHARGED-PARTICLES IN A RADIO-FREQUENCY AFTERGLOWPLASMA CONTAINING NEGATIVE-IONS, JPN J A P 1, 35(8), 1996, pp. 4494-4497
Temporal behavior of charged particles in pure He and He-SF6 radio fre
quency (rf) afterglow plasmas has been experimentally clarified for va
rious SF6 gas concentrations (1, 25, 50%). The electron density in the
pure He plasma increased just after the rf power was switched off, un
like in a pure Ar plasma, and then decreased slowly. The increase was
probably due to collisional ionization of metastable He atoms. The ele
ctron density in the He-SF6 plasmas decreased exponentially. This was
due to electron attachment to various molecules in the afterglow plasm
a.