Fowler-Nordheim injection in NO nitrided gate oxides, grown on n-type 4H-SiC, has been investigated at room temperature and 300 degrees C. The results show that NO increases the electron injection barrier height to a value which is very close to the theoretical value at room temperature. Excessive temperature dependence of the electron injection barrier height is also significantly reduced by the nitridation. (C) 2000 Elsevier Science Ltd. All rights reserved.