Speaker
Description
DC bias diode and DC magnetron plasma sputtering are used at CERN for niobium thin film deposition on copper radio-frequency accelerating cavities.
A dedicated test bench has been developed to perform detailed plasma characterization in these two sputtering configurations. It consists of a cylindrical magnetron assembly, in which two swept Langmuir probes actuated by independent rotation and translation motion feedthroughs are used. Plasma density and electron temperature profiles can be reconstructed with axial and combined radial/azimuthal resolution.
Plasma characteristics resulting from simulations with a commercial 3D Particle-In-Cell/Monte Carlo code are compared with the experimental data for different pressures.
Perspectives for coating optimization applied to real cavities are discussed.
