Effective reactive pulsed magnetron sputtering of aluminium oxide – Properties of films deposited utilizing automated process stabilizer

Abstract

The formation of dielectric composites on a target surface (target poisoning) reduces the deposition rate of a reactive magnetron deposition process in comparison to the deposition rate of metals. One way of minimizing this reduction is shifting the magnetron operating point from the dielectric to the transient mode. The goal of this paper is to show that a stable process of efficient aluminium oxide deposition can be carried out in a transient mode. An automated stabilizer driven by the electrical parameter of the magnetron power supply was used for process stabilization. The approach of process stabilization in the transient mode resulted in about seven times higher deposition rate of aluminium oxide than that of a standard dielectric mode and only two times lower than the deposition rate of aluminium. The optical properties of the thus obtained aluminium oxide films were studied by means of ellipsometric analysis. The model of film structure, consisting of stoichiometric aluminium oxide, metallic inclusions and voids, was proposed and dispersion characteristics were calculated. The complex refractive index characteristics were similar to those typical of aluminium oxide deposited during a standard pulsed reactive magnetron sputtering process.