Fabrication and Experimental Validation of Low Inductance SiC Power Module with Integrated Microchannel Cooler

With similar to 3x larger energy bandgap compared to silicon (Si), silicon carbide (SiC) power devices offer lower specific conduction resistances and faster switching speed, enabling a more efficient and compact power converter design. However, the high voltage overshoot during fast switching transients and the thermal management challenges in compact power converters are still key limitations to fully exploit SiC's high performances. In this paper, a wire-bondless (flip-chip bonding) SiC power module is proposed to achieve ultra-low power loop inductances (0.93 nH). Meanwhile, a microchannel cooler is etched on the direct bond copper (DBC) substrate of the SiC module by femtosecond laser to achieve low bonding surface roughness and channels uniformity. The DBC based microchannel cooler eliminates the solder layer, baseplate, thermal interface material and part of cooler, demonstrating 65% lower chip junction-to-coolant thermal resistance (similar to 0.073 cm(2)K/W) than conventional forced liquid cooling methods. A corresponding fabrication process is developed to integrate the microchannel cooler within the power module, enabling co-optimization of high power density and thermal performances. To validate the switching and thermal performance of the low inductance SiC power module with integrated microchannel cooler, a 200 kHz hard switching boost converter is designed and developed.