Embodiments disclosed herein include methods of forming high quality silicon nitride films. In an embodiment, a method of depositing a film on a substrate may comprise forming a silicon nitride film over a surface of the substrate in a first processing volume with a deposition process, and treating the silicon nitride film in a second processing volume, wherein treating the silicon nitride film comprises exposing the film to a plasma induced by a modular high-frequency plasma source. In an embodiment, a sheath potential of the plasma is less than 100 V, and a power density of the high-frequency plasma source is approximately 5 W/cm2 or greater, approximately 10 W/cm2 or greater, or approximately 20 W/cm2 or greater.