Characterization of fast 4.5 kV SiC p-n diodes

New results of silicon carbide p-n diodes show a promising performance for high voltage applications. The diodes are characterized by high power ratings, temperature stability, rugged avalanche and fast switching behavior. Significant savings in system cooling equipment seem possible. However, with today´s available material the device areas and thereby current ratings which can be fabricated with reasonable yield are restricted to a few square mm resp. a few amps. The SiC p-n diodes are fabricated with implanted p-regions on 39 μm thick n-type epitaxial layers with a doping concentration of 2×10¹⁵ cm^-3. They exhibit a stable avalanche breakdown at 4800 V and a low leakage current (<20 μA/cm²) prior to breakdown. The on-state is characterized by a voltage drop of 4.0 V at a current density of 100 A/cm², corresponding to 2.2 A. For current densities above 80 A/cm² lower static losses have been achieved compared to equivalent silicon high voltage diodes. The temperature coefficient is slightly positive guaranteeing a homogeneous current sharing for operation in parallel. The switching performance is characterized by very low dynamic losses. The reverse recovery current peak is considerably lower than the forward current, with a reverse recovery time as short as 30 ns