Selection criteria for sealing glasses for SiC packaging

Three very different commercial glasses were chosen for their close matched coefficient of thermal expansion with SiC and were tested in view of their application as glass sealants for SiC packages. The occurrence of bubbles at the glass/SiC interface was attributed to the reaction between the SiC substrate and certain oxides present in the glasses forming CO gas. Selection criteria were developed based on thermodynamic calculations in order to determine which glass composition would be stable with SiC. This approach provides valuable information in tailoring suitable glasses for the demanding applications that SiC materials may encounter in packaging for high temperature applications.