Studies of a sheath structure in an RF discharge using experimental, analytical, and simulation approaches

Electric field distributions in a helium RF discharge in a collisional regime were measured using laser-induced fluorescence. The measured distributions and sheath thicknesses obtained from the electric field distributions were compared with those obtained from an existing analytical theory and with a numerical simulation, together with the thicknesses obtained using the Child-Langmuir law for a DC discharge. The comparison yielded reasonable agreement, both in general tendency with regard to the pressure dependence and in the absolute magnitude. These results provide, for the first time, evidence of the validity of these analytical and simulation approaches.