Comparative Study on Power Cycling Capabilities of SiC Power MOSFET and Si IGBT Baseplate-less Power Modules

This paper presents a comparative study on power cycling (PC) capabilities of SiC power MOSFET and Si IGBT baseplate-less power modules with sintered and solder die attach, based on PC experiments and electro-thermo-mechanical (ETM) simulations. A comprehensive failure analysis after the PC confirms that the bond wire degradation occurred for all modules. However, only SiC power MOSFET modules with solder die attach showed significantly lower PC lifetime, and failed by solder degradation as dominant failure mode. Even though a shorter lifetime can be expected for SiC power MOSFET modules due to higher Young's modulus of SiC, a comparable PC lifetime of the SiC power MOSFET modules with sintered die attach and the Si IGBT modules with both solder and sintered die attach was achieved. Using the ETM simulations, this was attributed to significant effects of current density and wire geometry on bond wire lift-off. Furthermore, the results point out that the available lifetime models proposed for Si IGBT and SiC power MOSFETs modules have to be revisited.