Methods and apparatuses are provided herein for oxidizing an annular edge region of a substrate. A method may include providing the substrate to a substrate holder in a semiconductor processing chamber, the semiconductor processing chamber having a showerbead positioned above the substrate holder, and simultaneously flowing, while the substrate is supported by the substrate holder, (a) an oxidizing gas around a periphery of the substrate and (b) an inert gas that does not include oxygen through the showerhead and onto the substrate, thereby creating an annular gas region over an annular edge region of the substrate and an interior gas region over on an interior region of the substrate; the simultaneous flowing is not during a deposition of a material onto the substrate, and the annular gas region has an oxidization rate higher than the interior gas region.