Embodiments of the invention provide methods for depositing a material on a substrate within a processing chamber during a vapor deposition process, such as an atomic layer deposition (ALD) process. In one embodiment, a method is provided which includes sequentially exposing the substrate to a first precursor gas and at least a second precursor gas while depositing a material on the substrate during the ALD process, and continuously or periodically exposing the substrate to a treatment gas prior to and/or during the ALD process. The deposition rate of the material being deposited may be controlled by varying the amount of treatment gas exposed to the substrate. In one example, tantalum nitride is deposited on the substrate and the alkylamino metal precursor gas contains a tantalum precursor, such as pentakis(dimethylamino) tantalum (PDMAT), the second precursor gas contains a nitrogen precursor, such as ammonia, and the treatment gas contains dimethylamine (DMA).