A method and system for plasma-assisted thin film vapor deposition on a substrate is described. The system includes a process chamber including a first process space having a first volume, a substrate stage coupled to the process chamber and configured to support a substrate and expose the substrate to the first process space, a plasma generation system coupled to the process chamber and configured to generate plasma in at least a portion of the first process space, and a vacuum pumping system coupled to the process chamber and configured to evacuate at least a portion of the first process space. The system further includes a process volume adjustment mechanism coupled to the process chamber and configured to create a second process space that includes at least a part of the first process space and that has a second volume less than the first volume, the substrate being exposed to the second process space.