Infineon’s CoolSiC™ trench-based silicon carbide power MOSFETs represent a dramatic improvement in power conversion switching device Figure Of Merit (FOM) values with outstanding system performance. This enables higher efficiency, power density, and reduced system cost in many applications and new technology.
However, as with all new technologies, it is essential that thorough technology development and product qualification procedure is followed. Only in this way can design lifetime and quality requirements for power conversion systems be achieved.
Despite the similarities to silicon—e.g., the vertical device structures, the presence of a native oxide like SiO2, or the majority of processing steps—there are still important differences related to the material properties itself and the operating modes of these new power devices. As these differences are substantial, their impact on the operation in the final application and on the required development and reliability qualification processes must be carefully considered.
This paper describes the major steps in the release process that Infineon has used to successfully qualify CoolSiC™ technology and products. Key failure mechanisms are described, and the means to ensure safe and reliable operation in a wide variety of applications are provided. Through this approach, many risks our customers would otherwise encounter are avoided and a safe path to the reliable use of Infineon CoolSiC™ technology is provided. This publication also holds tutorial value to engineers with an interest in a better understanding of SiC-related reliability.