High quality ultrathin silicon oxynitride films (3.5 nm) have been grown in a nitric oxide ambient using rapid thermal processing. The physical and electrical properties of these films are compared with those formed in a nitrous oxide environment. X‐ray photoelectron spectroscopy (XPS) results show that the nitric oxide (NO) grown films have a significantly different nitrogen distribution compared to the nitrious oxide (N2O) grown films. The capacitance‐voltage and current‐voltage characteristics of the NO grown and NO‐modified films are, in general, better than those of the same thickness grown in either N2O or O2.