Characterization of Ar:N₂ plasma mixture with optical emission spectroscopy during deposition of NbN coating

   The combination of optical emission spectroscopy with models of plasma light emission represents a non-intrusive and adaptable approach for determining plasma characteristics.

   This study aimed to investigate the plasma electron temperature, electron density, and other parameters of plasma within context DC magnetron sputtering, under a various experimental condition, in the existence of a Niobium target and an Argon:Nitrogen gas mixture.

   To evaluate electron temperature and electron density, optical emission spectroscopy was employed at a range of discharge voltages (400–800 V) and gas pressures (0.04–3.3 mbar). The measurements were taken during the deposition of a Niobium nitride coating with in magnetron sputtering setup, maintaining a gap distance of 0.06 m and a total flow rate of 40 Standard Cubic Centimeters per Minute. The temperature of electron was assessed using Boltzmann plot strategy with several ion lines Ar⁺ lines, while density of electron was determined from the intensity ratio of atomic to ionic lines using Saha-Boltzmann equation. The results demonstrate that, for the plasma under investigation, an increase in the applied voltage lead to an elevation of temperature of electron, while an increase in the working pressure results in a reduction in the temperature of electron. Conversely, the density of electron decreases with the increasing applied voltage and increases with rising working pressure. Additionally, the findings indicate that the introduction of a modest quantity of nitrogen gas into the discharge source resulted in improved electrical characterization of the glowing discharge plasma during the Niobium nitride coating deposition process.

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