DUAL-UNBALANCED MAGNETRON DEPOSITION OF TIN FILMS

Recently it has been demonstrated that "unbalanced" magnetrons can be used very effectively to provide increased ion current densities incident on the substrate surface, allowing deposition at reduced ion energies without sacrificing film density, hardness, or adhesion. The effects of this type of high-flux, low-energy ion bombardment during film growth are currently under investigation in a number of research laboratories; however, the majority of these studies have been made using single-cathode systems. The unique dual-cathode geometry used in this research eliminates the shadowing effects commonly encountered when coating three-dimensional components in single-cathode systems. Numerically and experimentally determined magnetic characteristics are related, via plasma and deposition parameters, to the microstructures and properties of the resulting TiN films. In this work, two specific cathode arrangements are considered for which the strength of the magnets in both cathodes are the same and only the interrelationship between the two cathodes is altered, by reversing the orientation of the magnets in one cathode with respect to the magnets of the other cathode, so that the north poles of one cathode face the south poles of the other cathode directly across the chamber. This simple alteration in the orientation of the magnets in one cathode results in very large changes in the magnetic relationship between the two cathodes and gives rise to variations in the plasma and deposition characteristics. The final outcome is the production of TiN films with differing properties and structures.