Influence of epitaxial growth and substrate-induced defects on the breakdown of 4H-SiC Schottky diodes

Morphological defects and elementary screw dislocations in 4H-SiC were stud ied by high voltage Ni Schottky diodes. Micropipes were found to severely l imit the performance of 4H-SiC power devices, whereas carrot-like defects d id not influence the value of breakdown voltage. The screw dislocation dens ity as determined by x-ray topography analysis under the active area of the diode was also found to directly affect the breakdown voltage. Only diodes with low density of screw dislocations and free from micropipes could bloc k 2 kV or higher. (C) 2000 American Institute of Physics. [S0003-6951(00)01 119-0].