A Double-Side Cooled SiC MOSFET Power Module Based on Hermetic Conformal Coating for 250 °C High Temperature Applications

Hermetic conformal coating (HCC) employs hermetic sealing to safeguard the internal circuit, while incorporating an ultra-thin conformal coating to enhance insulation with minor thermomechanical stress, enabling 250°C operation ability for the SiC power module. However, conventional outer hermetic sealing methods are incompatible with double-side cooled (DSC) module due to prohibitive increases in thermal resistance and parasitic inductance. To address this issue, an inner hermetic sealing method leveraging the inherent parallel-substrate layout of DSC modules together with specially designed inner hermetic ceramic cases is proposed in this article to integrate HCC in DSC module without electrical or thermal performance degradation. A half-bridge DSC SiC power module based on hermetic conformal coating is developed for extremely high-temperature applications. Finite element analysis (FEA) simulation results show that, compared to the conventional hermetic sealing method, the proposed approach reduces both the junction-to-case thermal resistance (Rth_jc) and the module parasitic inductance (Lmodule) by over 75%, enabling 250°C operation ability for the DSC module without compromising its original thermal and electrical performance advantages. Subsequently, static and dynamic characteristics of the fabricated module are evaluated under temperatures up to 250 °C. Finally, continuous operation at 600 V and above 250 °C is conducted to verify the superiority of the proposed packaging method.