Embodiments described herein relate to methods for forming flowable chemical vapor deposition (FCVD) films suitable for high aspect ratio gap fill applications. Various process flows described include ion implantation processes utilized to treat a deposited FCVD film to improve dielectric film density and material composition. Ion implantation processes, curing processes, and annealing processes may be utilized in various sequence combinations to form dielectric films having improved densities at temperatures within the thermal budget of device materials. Improved film quality characteristics include reduced film stress and reduced film shrinkage when compared to conventional FCVD film formation processes.