Disclosed are methods of performing film deposition. The methods may include volumetrically isolating a first process station from a second process station by flowing a curtain gas between them, and igniting first and second plasmas supported by first and second plasma feed gases, while flowing the curtain gas, to cause film deposition at the first and second process stations. The curtain gas and the first and second plasma feed gases may each include a high-breakdown voltage species that may be molecular oxygen. The high-breakdown voltage species may have a breakdown voltage of at least about 250 V for a pressure-distance (pd) value of 3.4 Torr-cm. The curtain gas may have a higher concentration of the high-breakdown voltage species than the first and second plasma feed gases. The high-breakdown voltage species may make up about 5-50% of the curtain gas by mole fraction. The high-breakdown voltage species may be molecular oxygen.