1.2kV SiC Merged PiN Schottky Diode with Improved Surge Current Capability

In this work, a novel structure design concept (plasma spreading layers, PSL) is introduced into the SiC MPS diode which can significantly improve the surge current capability. The plasma spreading layers can spread bipolar current from the wide P+ region to the other parts and alleviate unbalanced current distribution in the device during the surge conditions, thus, device’s surge capability can be improved. The proposed structure can achieve a better tradeoff relation between the device forward voltage drop at nominal current and surge capability. 1.2kV SiC MPS diodes with two types of plasma spreading layers are designed and fabricated in this work, their forward characteristics and surge current capability are compared to traditional stripe cell design and hexagonal cell design. The results show that a 20% increase of maximum allowed energy is achieved by the new structure design comparing to the traditional hexagonal design, which results in a 10% improvement of the surge current capability.