Thermodynamic Temperature and Density of Ar(I) for 4S[1/2]0 State in a Facing Target Sputtering System

The 4S' [1/2]0 → 4P' [3/2]1 transition of Ar(I) in a facing target sputtering chamber is measured using a Ti:sapphire ring laser at several operating conditions. Doppler width and line intensity are determined by analysis using the Voigt function. The thermodynamic temperature determined from the Doppler width increases linearly with discharge current and gas pressure. The population density from the line intensity is reduced to the reference temperature obtained by interpolating the discharge current to zero. The empirical relationship to describe population density at a discharge current and a gas pressure is discussed.