Observation of the Electric Field Structure in the Sheath of Electronegative Plasmas by Laser-Induced Fluorescence-Dip Spectroscopy

We have measured the distribution of the electric field in the sheath formed between electronegative Ar⁄SF6 plasmas and a biased electrode by laser-induced fluorescence-dip spectroscopy. It has been found for the first time that the electric field in the sheath of an electronegative plasma has a multistage structure, which may be due to the reflections of negative ions and electrons at different distances from the electrode surface.