Microstructure Evolution and Online Thermal Resistance of Ag Sintered SiC/DBA Power Module During Power Cycling

Abstract

With the increasing power and miniaturization of power electronics, the power cycling reliability and thermal management of power modules have become increasingly crucial. To address this issue, our Lab. has developed a novel instrument that allows simultaneous power cycling and real-time thermal resistance measurement. Utilizing this specific instrument, we investigated the microstructural evolution of the die attachment layer during power cycling and monitored the real-time thermal resistance of the SiC-TEG (Silicon Carbide-Thermal Engineering Group) heater chip/sintered Ag/DBA (Directed Bonded Aluminum with ceramic core of Si3N4) structure. Additionally, strategies to improve the degradation of the microstructure were proposed. The results indicate that after 10000 power cycles, numerous cracks were observed in the sintered Ag layer. However, the addition of 5 wt. % A1 suppressed the generation of cracks significantly. The addition of A1 particles has little effect on the transient thermal resistance during power cycling.