An apparatus and method for depositing a transition metal nitride film on a substrate by atomic layer deposition in a reaction space defined by an at least one chamber wall and showerhead is disclosed. The apparatus may include, a substrate support disposed within the reaction space, the substrate support configured for supporting at least one substrate and a temperature control system for controlling a temperature of the at least one chamber wall at those portions of the at least one chamber wall that is exposed to a vapor phase reactant. The apparatus may also include a temperature control system for controlling a temperature of the showerhead, wherein the temperature control system for controlling a temperature of the showerhead is configured to control the temperature of the showerhead to a temperature of between approximately 80° C. and approximately 160° C. The method may include, providing at least one substrate on a substrate support within the reaction space and controlling a temperature of the at least one chamber wall at least at those portions of the at least one chamber wall that is exposed to a vapor phase reactant and controlling a temperature of a showerhead. The method may also include, alternatively and sequentially feeding at least two vapor phase reactants into the reaction space, wherein the temperature of the showerhead is controlled to a temperature between approximately 80° C. and approximately 160° C.