In this paper, the determination of the defects induced by 20 MeV Au irradiations in hexagonal silicon carbide single crystals is discussed. The evolution of the irradiation-induced defects as a function of the ion fluence has been studied as a function of depth below the surface using 0.5-25 keV positron beam based Doppler annihilation-ray broadening spectrometry. Results show the detection of two different kinds of defects, depending on the ion fluence. (C) 2008 Elsevier B.V. All rights reserved.