Methods for depositing film on substrates are described. In various cases, a high thermal conductivity gas such as helium is used to deposit a conditioning layer on surfaces of the reaction chamber before it is used to process substrates. The helium may be used to help atomize/vaporize a liquid reactant in a heated injection module before the reactant is delivered to the reaction chamber. In some embodiments, a purge gas including helium is used during a post-deposition purge during deposition on substrates. The disclosed embodiments allow for mixed recipe processing without having to clean the reaction chamber between recipes, and without forming a high number of particles/defects on the substrates. This allows for an improved throughput of high quality film, even where mixed recipes are used in a single reaction chamber.