CORRELATIONS OF PLASMA PROPERTIES AND MAGNETIC-FIELD CHARACTERISTICS TO TIN FILM PROPERTIES FORMED USING A DUAL UNBALANCED MAGNETRON SYSTEM

A number of single-cathode "unbalanced" magnetron systems have recently been developed to obtained increased ion-current densities at the film surface during hard coating deposition; however, as with most single-cathode systems, shadowing effects often limit the types of substrates that can be coated in these units. The deposition system employed in this research utilizes a unique dual-cathode unbalanced dc-magnetron arrangement to coat specimens mounted on a rotational substrate holder, thereby gaining the benefits of unbalanced magnetrons while eliminating the shadowing effects commonly associated with single-cathode systems. This paired unbalanced magnetron system can be used to create a well-confined discharge, yielding high substrate ion-current densities (> 5 mA/cm2). In order to evaluate the effects of "unbalancing" on the depositional environment, the plasma and magnetic field characteristics are related to TiN film microstructures, properties, and crystallographic orientations. Microstructural investigations performed using scanning electron microscopy and cross-section transmission electron microscopy have demonstrated that the films possess fine columnar grain structures with no observable layering, and they are very near full density at substrate bias potentials of - 85 V and less.