Experimental investigation of edge-to-center density ratio in inductively coupled plasmas

Abstract

Edge-to-center density ratios were measured by using a floating harmonics method in inductively coupled plasma (ICP) and were compared to the theoretical model. As the gas pressure increased, the plasma density at the center increased. However, plasma density at the edge showed a different trend; it had a maximum value at 10 mTorr with increasing gas pressures, regardless of ICP powers. This unexpected result could be explained by a global power balance equation.