The feasibility of bipolar diodes with high blocking voltages realized on epilayers grown on n(+) 6H-SiC Lely substrates by sublimation epitaxy with minimal doping level about 3x10(15) cm(-3) but with "non uniform" doping profile was demonstrated. PN junctions have been realized by a triple implantation of Al. A surrounding junction termination extension region has been realized by a 4-fold implantation of Al. At reverse bias diodes has relatively stable breakdown in the 1000V range. Values of the experimental breakdown voltage are in agreement with calculated values on diodes with the smallest diameter (200 Pin). At room temperature and the current density 300 A/cm(2) the forward voltage drop is about 5V. Rectifying properties of these diodes were examined up to T=1080 K.