Abstract: A method and apparatus for low temperature deposition of doped silicon nitride films is disclosed. The improvements include a mechanical design for a CVD chamber that provides uniform heat distribution for low temperature processing and uniform distribution of process chemicals, and methods for depositing at least one layer comprising silicon and nitrogen on a substrate by heating a substrate, flowing a silicon containing precursor into a processing chamber having a mixing region defined by an adaptor ring and one or more blocker plates and an exhaust system heating the adapter ring and a portion of the exhaust system, flowing one or more of a hydrogen, germanium, boron, or carbon containing precursor into the processing chamber, and optionally flowing a nitrogen containing precursor into the processing chamber.