Atomic oxygen, which can be liberated as an intermediate product in the decomposition of N2, is shown to be effective in removing N previously incorporated in SiO2 layers grown in N2O. This removal results in a N distribution that is sharply peaked at the Si–SiO2 interface for oxides grown in N2O by rapid thermal oxidation, but in a flat N distribution for N2O oxides grown in a furnace where the concentration of atomic oxygen is generally not substantial at the wafer position. This effect provides a means of tuning N profiles in a manner that may be useful for optimizing oxide quality.