Macroparticle Reduction and Its Transport Mechanism through a Magnetic Filter during Cathodic Vacuum Arc Deposition with an HEA Target

Abstract

By cathodic arc deposition, the effects of the magnetic field, working pressure, inner-wall structure, and cross-section area of the magnetic-filter duct on the macroparticle (MP) distribution were investigated with a high-entropy alloy target. The MP density increased with the density of the plasma beam transporting through the filter duct, which was increased by the magnetic field or working pressure. In order to reduce the MP density, equally spaced circumferential Cu-sheet baffle and lining of 304-stainless-steel wire mesh were used as the inner-wall structure, respectively, but the improvement was limited. However, inserting an Al foil disk with a round opening for the passage of the main plasma stream at the bend position of the duct remarkably reduced the area fraction of the MPs from 4.8% to 0.6%. These results demonstrate that the main transport mechanism of the MPs was the entrainment in the plasma beam through the duct. In addition, reducing the cross section of the filter duct was suggested to be an effective method to reduce MPs. This method could be utilized for high-MP generation targets such as high-entropy alloys.