Characterization of 4H-SiC PiN Diodes Formed on Defects Identified by PL Imaging

Abstract

In this paper the results of a study in which the surface quality of 30, 35 and 110 µm 4H-SiC epitaxial layers from different manufacturers are evaluated using AFM and photoluminescence (PL) imaging. PiN diodes are then intentionally fabricated on triangular defects and polytypes grains which are formed, in order to understand their impact on the resulting electrical characteristics, which includes on-state behaviour, turn-on characteristics and reverse leakage current behaviour. The results indicate that the defects form a high resistance short through the p-type anode. This results in higher leakage current, well over 108 times higher than the devices formed off-defect. PiN diodes fabricated on-defect also suffered from soft breakdown unlike those off-defect.