Embodiments related to metal oxide protective layers formed on a surface of a halogen-sensitive metal-including layer present on a substrate processed in a semiconductor processing reactor are provided. In one example, a method for forming a metal oxide protective layer is provided. The example method includes forming a metal-including active species on the halogen-sensitive metal-including layer, the metal-including active species being derived from a non-halogenated metal oxide precursor. The example method also includes reacting an oxygen-containing reactant with the metal-including active species to form the metal oxide protective layer.