The presence of defects on 4H-SiC wafers was carefully evidenced by different kinds of techniques such as optical microscopy and scanning electron microscopy. Highlighted defects were also analyzed by atomic force microscopy and profilometer technique. Schottky diodes were fabricated on investigated wafers in order to obtain informations about the correlation between defects and electrical proper-ties of the devices. Electrical characterization has shown the influence of defects in voltage reverse breakdown and Deep Level Transient Spectroscopy has evidenced the presence of two main centers of recombination.