Magnetron sputtering process for homogeneous internal coating of hollow cylinders

A magnetron sputtering system to coat tubes and hollow bodies with functional thin films on their internal surface was designed, constructed, and successfully set up. A rod of the coating material is drawn coaxially through substrate body and serves as the target, and a magnetic field is applied to enhance the plasma intensity and to control the deposition process. Generated by a system of external coils, the magnetic field is subdivided into five adjustable sectors. This allows a local adjustment of the plasma intensity and the control of the deposition process, e.g., for the improvement of film homogeneity, the local modification of film structures, or the introduction of graded thickness profiles.