High Temperature Packaging for SiC Power Transistors

Abstract

Power transistors based on silicon carbide (SiC) are now commercially available. They have a higher efficiency and higher voltage blocking capabilities than conventional silicon devices. The wide-band gap and chemical inertness of SiC makes it suitable to high temperature operation. However, there is a need for new packaging for power transistors that can operate in higher temperatures. We have developed a package based on ceramics and silver for high temperature operation of SiC power transistors. Three types of SiC devices from different manufacturers are packaged and tested in room temperature. Though the devices were still functional after the packaging process, their performance seem to have degraded. This could be a result of the high temperature packaging process and the measurement setup. FEM simulations are also performed to investigate the thermo-mechanical behavior of the package. The target operating temperature of the package is 400 °C. Modeling show stress concentrations at the corners of the device chip and suggests that this stress is decreased if the substrate metallization is changed from copper to silver.