The invention relates generally to processes for enhancing the deposition of noble metal thin films on a substrate by atomic layer deposition. Treatment with gaseous halides or metalorganic compounds reduces the incubation time for deposition of noble metals on particular surfaces. The methods may be utilized to facilitate selective deposition. For example, selective deposition of noble metals on high-k materials relative to insulators can be enhanced by pretreatment with halide reactants. In addition, halide treatment can be used to avoid deposition on the quartz walls of the reaction chamber.