There is a trade-off between nominal forward current density and surge current capability for 4.5kV SiC MPS diodes. This paper explains the physical mechanisms underlying this trade-off and identifies the relevant design parameters. The dependencies of this trade-off on the layout parameters and physical parameters are described by analytical relations (compact model). An equivalent lumped element circuit is set up for an intuitive interpretation of the functional components of a SiC MPS diode. Eventually, we investigate several novel device structures with a view to improving the forward characteristics under regular and overcurrent operating conditions

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.

This paper presents the use of innovative high-voltage SiC diode technology in the development of a user configurable full-wave or half-wave rectifier bridge. The devices are of merged Junction-Barrier-Schottky (JBS) type to enable for optimum performance even in the presence of current surges, as demanded by the application. To contain the cost of the proposed solution, their packaging relies on Insulated Metal Substrates (IMS), as opposed to conventional ceramic type substrates. The layout and module pin terminations are chosen to yield optimum electrothermal and electro-magnetic performance in compatibility with a standard solder and wirebond assembly process. Preliminary functional static characterization tests at different temperatures are also presented.