Measurements of spatial distributions of electron density and temperature of 450 MHz UHF plasma using laser Thomson scattering

Abstract

A capacitively coupled Ar plasma was produced by the ultra-high frequency power source (450 MHz) and the plasma parameters were studied by laser Thomson scattering. It was found that a very high density plasma with a low electron temperature was realized; the electron density ne is around (1.1–1.5) × 1018 m−3 and the electron temperature Te is around (1.7–2.1) eV. Radial profiles of ne and Te were obtained for different pressures and powers. In all the conditions explored, ne had a single-center-peak profile, while Te profiles were relatively flat along the electrode.