A method of depositing a film on a substrate is provided. The method includes positioning the substrate on a substrate support in a chamber and depositing the film on the substrate using a DC magnetron sputtering process in which an electrical bias signal causes ions to bombard the substrate. The substrate support includes a central region surrounded by an edge region, the central region being raised with respect to the edge region, and the substrate is positioned on the central region so that a portion of the substrate overlays the edge region and is spaced apart therefrom.