4.5 kV SiC Junction Barrier Schottky Diodes with Low Leakage Current and High Forward Current Density

Abstract

High-voltage 4H-SiC Junction Barrier Schottky diodes with a reverse breakdown voltage of over 4.5 kV and a turn-on voltage below 1 V have been fabricated. They achieved a forward current of 5 A at a forward voltage drop of 1.8 V and 20 A at 4.2 V. A low reverse leakage current of 0.3 μA at 1.2 kV and 37 μA at 3.3 kV was measured. The chip size was 7.3 mm x 7.3 mm, the active area 0.25 cm2 and the diode was able to handle a repetitive pulse current density of over 300 A/cm2 without degradation. Floating field rings in combination with a field-stop ring were used as edge termination to reach 73 % of the theoretical breakdown voltage. The epitaxial layer was 32 μm thick, with a nitrogen doping concentration of 1 x 1015 cm-3. The JBS diodes have been manufactured in a 100 mm SiC prototyping line, using well established processing technology, to achieve cost-efficient devices.