Enhanced Thermal-Electrical Interconnect for Single-Sided Cooling SiC MOSFET Power Device Based on Polycrystalline Diamond

The silicon carbide (SiC) mosfet has attracted significant attention due to its superior theoretical properties. However, the conventional top-surface interconnect, wire bonding, in power devices is unable to manage heat effectively. Furthermore, the smaller size of the SiC mosfet dies makes the heat spreading problem more severe, thus restricting the operation current. To enhance the thermal performance of the SiC mosfet power device by using both surfaces of the die, this article presents a thermal-electrical interconnect (TEIC), whose main component is chemical vapor deposition polycrystalline diamond (PCD). Utilizing copper plating, copper-filled vias, and high-thermal-conductivity insulated substrate, the proposed PCD TEIC achieves electrical connections and efficient heat dissipation simultaneously. Theoretical modeling and simulations are employed to clarify the improvement in steady-state thermal behavior. The electrical and reliability characteristics are also simulated to comprehensively evaluate the performance of the proposed PCD TEIC. Finally, experimental tests are conducted to assess the thermal and reliability performance. The results show that the device with the proposed PCD TEIC has a significant reduction in thermal resistance and satisfactory reliability performance.