Schottky diodes were prepared on n-type silicon carbide (4H-SiC) substrates by deposition of ruthenium dioxide contacts. Their electrical and electronic properties were investigated by current voltage (I-V) and capacitance-voltage (C V) methods, and deep level transient spectroscopy (DLTS). Five deep energy levels with thermal activation energies of approximately 0.27, 0.45, 0.56, 0.58 and 0.85 eV referenced to the conduction band minimum were revealed. The two energy levels at 0.56 and 0.85 eV are presumably induced by divacancies and the incorporation of ruthenium impurities into the SiC interfacial region. The Schottky diode structures are typical with a barrier height of 0.88 eV, and the I-V characteristics signify a saturation current of 10 pA with an ideality factor of 1,28. Crown Copyright (c) 2006 Published by Elsevier B.V. All rights reserved.