Electron transport near oxidized SiC surfaces appears to be significantly deteriorated by interface defects. In contrast to oxidized Si, the SiC/oxide interface imperfections expose a remarkable resistance to post-oxidation treatments, suggesting these to be related to stable bonded configurations of the interfacial atoms (carbon clusters, oxide defects). Additionally, the SiO(2) layers grown on SiC are prone to degradation under current injection conditions at elevated temperature, which might limit the use Of SiO(2) as gate insulator. Possible solutions of these problems, using both thermal oxidation and an alternative insulating material, are discussed.