The trapping characteristics of thin oxynitride films obtained by the oxidation of a thermally nitrided silicon surface were studied under both tunneling and hot electron injection. Comparison with standard oxide layers yields the following differences: No net positive charge generation is observed in the investigated layers, and the rate of surface states generation is about one order of magnitude smaller. The electron trap density is estimated to be ∼6×1017cm−3with a capture cross section of ∼10−17cm2.