Spectroscopic characterization and modeling of Ar/Cl$_{2}$ microwave glow discharge

Ar/Cl$_{2}$ microwave glow discharge was applied for plasma etching of niobium, metal of choice for superconducting radiofrequency accelerator technology. Etching rates were determined for different discharge parameters and results of these experiments are published elsewhere [1]. Simultaneously, plasma emission actinometry was used to estimate the absolute densities of Cl, Cl$^{+}$ and Cl$_{2}$ in the variable plasma conditions. These results, combined with results of discharge diagnostics, were compared with results obtained trough the modeling of Ar/Cl$_{2}$ discharge. We have calculated the electron-impact ionization rates of Cl$_{2}$ and its fragments for electron energy distribution present in bulk plasma. These ionization rates will be used for modeling of plasma etching process and comparing with experimentally determined etching rates.\\[0pt] [1]. M. Ra\v{s}kovic, et al., J. Vac. Sci. Technol. A \textbf{27} (2), 301 (2009).