Development of 6kV-class SiC-PiN diodes for high-voltage power inverter

We succeeded to develop the SiC-PiN diodes with the breakdown voltage V_BR of > 6 kV and active area of 16 mm². On-voltages at 25°C were 3.38 V at forward current density J_F of 100 A/cm² and 3.68 V at J_F of 200 A/cm². A negative shift of on-voltage was observed at the elevated temperatures. On-voltages at 125°C are 3.19 V at J_F of 100 A/cm² and 3.48 V at J_F of 200 A/cm². The avalanche breakdown was observed at 7.0 kV. The reverse recovery charge of SiC-PiN diode module, two paralleled chips mounted on DBC substrate, was as low as 11 μC at 125°C, while that of Si-PiN diode module with same current rating was 83 μC at the same temperature. By using hybrid pair module with Si-IEGTs and SiC-PiN diodes, we demonstrated the operation of prototype 3-level inverter with 378 kVA. We successfully confirmed the fast switching operation with 2 kHz, which is four times higher than conventional converters. The developed technology greatly reduces the size and the space of a high-voltage, high-power inverter systems.