A blocking layer of a non-volatile charge trap memory device is formed by oxidizing a portion of a charge trapping layer of the memory device. In one embodiment, the blocking layer is grown by a radical oxidation process at temperature below 500° C. In accordance with one implementation, the radical oxidation process involves flowing hydrogen (H2) and oxygen (O2) gas mixture into a process chamber and exposing the substrate to a plasma. In a preferred embodiment, a high density plasma (HDP) chamber is employed to oxidize a portion of the charge trapping layer. In further embodiments, a portion of a silicon-rich silicon oxynitride charge trapping layer is consumptively oxidized to form the blocking layer and provide an increased memory window relative to oxidation of a nitrogen-rich silicon oxynitride layer.