Magnetron with external magnet to increase the ion content in the flow of deposited atoms

Magnetrons are widely used for producing protective coatings on the surface of processing tools and for depositing metal and dielectric films in the electronics industry. The properties of the coatings are significantly dependent on ion bombardment of the growing film. At large distances from the magnetron, the part of ions in the flow of deposited atoms is insignificant because the plasma region is concentrated near the magnetron target. The location of the NdFeB ring magnet in front of the magnetron changes the configuration of the total magnetic field. As a result, a magnetic trap forms in which electrons are held in the discharge area. The efficiency of ionization of sputtered atoms increases. This leads to an increase of the ion current by an order of magnitude. The ion current density increases proportionally to the discharge current. The configuration of the plasma boundary and the distribution of the ion current density in the cross section depend on the axial displacement of the external magnet relative to the magnetron. An ion current density of 0.1–0.55 mA/cm$^2$ was obtained at a distance of 60–90 mm from the magnetron at the discharge voltage of 320–350 V and the current of 150–300 mA. A stable discharge glows in argon, oxygen and argon-nitrogen mixture at a pressure of 0.3–0.5 Pa.