An SiC-Based Half-Bridge Module With an Improved Hybrid Packaging Method for High Power Density Applications

Abstract

SiC devices have the potential to structure high power density converters; however, SiC devices have high d i /d t during switching. Therefore, the parasitic inductances in the power loop and gating loop must be reduced to restrain the induced voltage. This paper proposes a SiC-based, half-bridge (HB) module with a hybrid packaging method. Such a module is based on printed circuit board (PCB) plus direct bonding copper (DBC) structure. The DBC provides part of power loops, and the SiC bare dies can be directly soldered on these loops; the PCB provides another part of the power loops, as well as the gating loops. Such a design allows the power loops on the PCB to be soldered with those on the DBC directly; in the meantime, the SiC bare dies soldered on the DBC can be connected to the PCB with bounding wires. Such a structure provides extra degrees of freedom for design so that the parasitic inductances can be minimized by optimizing the current communication loops, driver locations, and the gating connections, and the heat can also be dissipated through the direct cooling structure easily. A 1200 V/24 A SiC HB module is fabricated with the proposed method in the laboratory, and based on the fabricated module, a synchronous buck converter with power density of 379.3 W/in3 is also structured. The double pulse test shows that the fabricated module can be switched within 10 ns and that the drain-source voltage overshoot is only 2.5%. The highest efficiency of the converter based on the fabricated module is up to 99.46%.