Influence of Epitaxial Growth and Substrate Induced Defects on the Breakdown of High-voltage 4H-SiC Schottky Diodes

Abstract

The influence of morphological and structural defects on high-voltage 4H-SiC Schottky diodes was studied. Micropipes were found as severely limiting the breakdown voltage of 4H-SiC power devices, where as carrot-like defects did not influence the value of breakdown voltage. The screw dislocation density as determined by X-ray topography analysis under the active area of the diode was also found to directly affect the breakdown voltage value. Only diodes with low density of screw dislocations and free from micropipes could block 2 kV or higher.