Oxidation apparatus and method for semiconductor process

An oxidation method for performing direct oxidation includes respectively supplying an oxidizing gas and a deoxidizing gas to the process field, and directly oxidizing a surface target substrates by use of oxygen radicals and hydroxyl group radicals generated by a reaction between the oxidizing gas and the deoxidizing gas. The oxidizing gas is supplied through an oxidizing gas nozzle extending over a vertical length corresponding to the process field and is spouted from a plurality of gas spouting holes formed on the oxidizing gas nozzle and arrayed over the vertical length corresponding to the process field. The deoxidizing gas is supplied through a plurality of deoxidizing gas nozzles having different heights respectively corresponding to a plurality of zones of the process field arrayed vertically and is spouted from gas spouting holes respectively formed on the deoxidizing gas nozzles each at height of a corresponding zone.