Silicon carbide power electronic module packaging

Abstract

Wide bandgap semiconductors such as gallium nitride (GaN) and silicon carbide (SiC) offer exciting opportunities in enhancing the performance of power electronic systems in term of improved efficiency as well as higher temperature operation. Both silicon carbide and gallium nitride power semiconductor devices offer a higher voltage handling capability over their silicon power semiconductor counterparts. In this paper, the design and packaging issues for SiC power electronic modules are discussed. Several SiC devices are usually connected in parallel to increase its current handling capability in power electronic module packaging. The paralleling of these SiC devices creates unbalanced parasitic inductances which affect the dynamic switching performance for these paralleled devices. Each of the paralleled SiC devices could have different initial peak currents due to their different parasitic inductances within the module. Moreover, their fast dv/dt of the drain voltages as well as the high di/dt of the drain currents can cause spurious switching behaviors in some of the paralleled SiC devices in the power module. Layout techniques can be used to mitigate these spurious switching behaviors. However, module construction architectures and as well as module package construction are required to further mitigate these parasitic inductances. One of the many advantages of the SiC power devices is high voltage handling capability. High voltage operation of the power electronic module requires careful reduction of electric field intensification within the device as well as the module. Encapsulations with the desired dielectric breakdown strength as well as temperature performance must be applied on top of these devices to prevent premature voltage breakdown. One of the salient features of the SiC power electronic modules is high temperature operation of greater than 175°C. For high temperature operations, proper die attach must be utilized. Nano silver sintering and transient liquid phase bonding are two high temperature die attachment techniques. For high temperature operation, reliability testing for these SiC power electronic modules must be carefully considered since there is no existing international standard for reliability testing for these high-temperature power electronic modules.