The growth of high-quality thin oxynitrides in nitric oxide (NO) ambient on n-type 6H-SiC substrate is reported, The performance and reliability of NO-grown oxynitride are compared with those of NO-annealed. N2O-grown, N2O-annealed and N-2-annealed oxides. NO-grown device shows the best interfacial properties and oxide reliability among all the samples. X-ray photoelectron spectroscopy analysis indicates the highest nitrogen pileup at the SiO2/SiC interface of NO-grown sample. Therefore, the best performance of NO-grown sample can be related to the fact that oxide growth in NO has the advantage of providing higher nitrogen accumulation at the SiO2/SiC interface and in the oxide bulk than the other growth techniques. (C) 2002 Elsevier Science Ltd. All rights reserved.