A New Expansion Trench Design for Enhanced Thermal Fatigue Life of Packaged SiC Power Devices

SiC power devices are the core components of power electronic systems, whose packaging technology directly affects device lifespan and performance. However, the majority of SiC power devices still rely on traditional silicon-based packaging technology, which limits the full utilization of the advantages of SiC materials. This paper proposes slotted design and applies them to welded packages and bolt-type packages of SiC Schottky diodes. By comparing and analyzing their thermal performance and thermo-mechanical behavior under temperature cycling, the results show that: if a copper baseplate with six annular slots replaces a single solid copper base, the average plastic work density (PLWK) of the solder layer in the two packages can be reduced by 62.16% and 75.80%. Furthermore, this text studies solder infiltration into the slots. When the slots of the two packages using six annular slots are completely filled, compared with traditional structures, the average PLWK of the solder layer in welded and bolt-type packages is still reduced by approximately 16% and 60%, respectively. Meanwhile, thermal resistance increases by less than 6% and 4%.