用于高温碳化硅功率器件的薄膜封装解决方案

Wide bandgap semiconductors like silicon carbide (SiC) are capable to operate at temperature above 250 °C. However, current encapsulations cannot work at temperature above 175 °C, making high-temperature (≥250 °C) packaging of SiC devices still a challenge. This article introduces an innovative high-temperature packaging scheme for SiC power devices, utilizing a multilayered Parylene HT/Al2O3 composite film (MPACF). By implementing a cross-stacked organic Parylene HT and inorganic Al2O3 multilayer structure, the pathway for external moisture and oxygen to reach the SiC chips at elevated temperatures is blocked, reducing the risk of moisture/oxygen contact and circumventing the thermal oxidation process associated with traditional organic packaging materials. After further modifying the interface between the encapsulation material and the substrate with a silane coupling agent, the adhesion strength has been significantly enhanced. The MPACF ensures a high operational temperature and a low coefficient of thermal expansion, effectively safeguarding the SiC devices in the hashed condition. Reliability tests including 1500 cycles of thermal shock ranging from −55 °C to 250 °C and 500 h high-temperature aging at 250 °C have been carried on the encapsulated SiC devices, the adhesion strength of MPACF is well preserved at 5B and the devices exhibited outstanding static characteristics and switching performance.