Insulation Properties and Design Techniques of Encapsulation Materials for Power Semiconductors

This study aims to analyze the electric field characteristics of encapsulation materials used in power semiconductor packages and propose optimal insulation design techniques. The research focuses on mitigating electric field concentration at the triple junction, a critical structural vulnerability where metal electrodes, ceramic substrates, and encapsulation materials meet. Simulations were conducted using COMSOL Multiphysics to evaluate the effects of various encapsulation materials, including epoxy compound, silicone gel, PDMS, and graphene nanofiller composites. Key design variables such as electrode spacing and substrate thickness were adjusted to assess their impact on electric field distribution and insulation performance. The results indicate that silicone gel demonstrates high dielectric strength and effectively mitigates electric field concentration near the triple junction. A comparison of encapsulation materials: epoxy compound, silicone gel, and PDMS revealed distinct insulation and electric field distribution characteristics, with the order of electric field concentration increasing as PDMS < silicone gel < epoxy compound. Although graphene nanofiller-enhanced epoxy was introduced to improve electrical conductivity and composite properties, it exhibited a tendency to increase electric field concentration near the triple junction.