Navigating Strategies to Mitigate Insulation Issues Within High Power Density (U)WBG Power Module Packages: A Comprehensive Review Emphasizing Alternative Encapsulation Materials

The future of packaging for power modules hinges on the advancement of (U)WBG) materials like SiC, AlN, and diamond. However, pushing these boundaries faces significant challenges in insulation systems, which must withstand the demanding parameters involved. The repercussions include high electric fields, space charge accumulation, electrical treeing, and partial discharge (PD), all of which can lead to power module failure. This paper delves into reviewing these challenges within insulation materials of (U)WBG power modules and recent research aimed at mitigating electric field stress at triple points (TPs) and addressing PD issues. Beginning with the issue of high electric fields at TPs, the paper explores space charge, electrical treeing, and PD problems within encapsulation materials under practical operating conditions, such as high frequency, and high temperatures. Various strategies to tackle these insulation challenges are thoroughly discussed. While three prevalent mitigation strategies can address electric field issues at TPs, their validation under high-temperature conditions of (U)WBG power modules remains relatively unexplored, suggesting a potential shift towards alternative encapsulation materials. It is observed that the high-temperature dielectric liquids emerge as a promising solution to address thermal stresses for temperatures up to 350 °C with their stable dielectric properties and breakdown strength under repeated tests. Overall, this review provides a valuable framework by outlining the limitations of current mitigation strategies and offering recommendations for future research endeavors, with a particular emphasis on alternative encapsulants.