A method of forming a dielectric stack on a pre-treated surface. The method comprises pre-cleaning a semiconductor wafer to remove native oxide, such as by applying hydroflouric acid to form an HF-last surface, pre-treating the HF-last surface with ozonated deionized water, forming a dielectric stack on the pre-treated surface and providing a flow of NH.sub.3 in a process zone surrounding the wafer. Alternately, the method includes pre-treating the HF-last surface with NH.sub.3, forming the stack after the pre-treating, and providing a flow of N.sub.2 in a process zone surrounding the wafer after the forming. The method also includes pre-treating the HF-last surface using an in-situ steam generation process, forming the stack on the pre-treated surface, and annealing the wafer after the forming. The pre-treating includes providing an inert gas flow in a process zone surrounding the HF-last surface, reacting hydrogen with an oxidizer in the process zone for a very short duration, and providing an inert gas flew in the process zone after the reacting.