Surge Current Ruggedness of Silicon Carbide Schottky- and Merged-PiN-Schottky Diodes

In the paper the surge current capability of different power diodes made of silicon carbide (SiC) providing Schottky- and merged-pin-Schottky (MPS) structures are investigated. The diodes were impinged with surge current pulses of different shape and time. Depending on the diodes and there structures, they provide a different responsiveness. In some cases apart from the diode design it´s time constant and the case influences the destruction limit of the surge current capability. There exist different destruction mechanisms. The destruction mechanism of MPS diodes of one diode type was the temperature limitation of the metallization melting point. While the surge current pulse the SiC diodes reaches astonishingly high temperatures at the epitaxy layer and the metallization. The diodes of a second diode type show destructive hot spots.