Morphology of Mo particles and their incorporation into the growing film during vacuum arc deposition

Abstract

Vacuum arc deposition opens the possibility to alter the surface of the substrate and growing film with the aid of a combined flux of multiply charged ions and microparticles. This plasma flux meets the substrate with a supersonic velocity. Therefore, the result of the interaction between the plasma and substrate, for instance the morphology of the microparticles sticking to the substrate, depends strongly on the angle between the substrate and cathode surfaces. Mo layers have been deposited on Cu and silica glass substrates by vacuum arc deposition. The targets of high-purity Mo have been produced by high-vacuum electron-beam multiple melting in specially designed water-cooled copper molds. The morphology of the microparticles on the film surface is investigated by means of quantitative metallography. A strong influence of the substrate position on the plasma flow is observed. The distributions of particle sizes, aspect ratios and angles between the axes of the cathode and elliptic particles have been studied as functions of the deposition time, current and distance from the cathode. While increasing the deposition time particles were continuously incorporated into the film disappearing from the surface.