Diagnostics of a non-equilibrium inductively coupled plasmas in argon

An apparatus including a robot manipulated optical system has been built to provide absolute emission data from an inductively coupled plasma operating in argon in non-equilibrium conditions. Data for the two-dimensional population densities of one of the excited states of neutral argon ArI are presented together with the Langmuir probe data for electron density and plasma potential. Measurements were performed at 500 mTorr and 50 mTorr and with 100 sccm flow of argon under the constant power condition, 100 W. The data show that excitation profile is almost identical to the radial profile of electron density. At higher pressure maximum excitation and electron density are produced close to the walls, while at low pressure maximum excitation is at the center of the vessel and a high field is formed close to the walls.