The electrical characteristics of Al/SiO2/n-Si structures containing epitaxial beta-SiC nanocrystals at the SiO2/Si interface prepared by a novel technique, namely by annealing of SiO2/Si structures in a CO-containing atmosphere at high temperatures, are compared with those of similar reference unannealed structures without SiC nanocrystals. The capacitance behaviour of structures with SiC nanocrystals exhibited features unusual for a MOS structure. However, opposite to the reference structures, there was a current flow through these structures. The current showed Schottky-like characteristics at low current level. The fact that the SiO2 layer became electrically conductive after a heat treatment in a CO-containing atmosphere, is very important for the possible optoelectronic applications of similar structures. (C) 2004 Elsevier B.V. All rights reserved.