A coating system includes a coating chamber having a peripheral chamber wall, a top wall, and a bottom wall. The peripheral chamber wall defines a chamber center. A plasma source is positioned at the chamber center. The coating system also includes a sample holder that holds a plurality of substrates to be coated which is rotatable about the chamber center at a first distance from the chamber center. A first isolation shield is positioned about the chamber center at a second distance from the chamber center, the first isolation shield being negatively charged.