ANALYSIS OF DC MAGNETRON DISCHARGES IN AR-N-2 GAS-MIXTURES - COMPARISON OF A COLLISIONAL-RADIATIVE MODEL WITH OPTICAL-EMISSION SPECTROSCOPY

DC magnetron discharges in argon-nitrogen gas mixtures have been chara cterized by optical emission spectroscopy (OES). Optical lines from th e cathode species (aluminium) and the gas mixture (argon, nitrogen) ha ve been measured at constant total pressure, as a function of the gas mixture composition and electrical power. The experimental data are co mpared with results of a theoretical plasma model which solves self-co nsistently the Boltzmann equation for electrons and the kinetic equati ons for aluminium, argon, molecular and atomic nitrogen states. The em ission intensity variations of plasma species have been analysed versu s the nitrogen relative concentration and electrical power and compare d with calculated populations of emitting species with a satisfactory agreement. The variation of aluminium density versus the nitrogen conc entration has been deduced by using the Al line intensity and excitat ion rates given by the model.