Thermal effects on fracture behaviors of the die-attachment in the SiC power device under power cyclic conditions based on fracture phase-field modeling

Abstract

SiC power devices are considered as one of the most prospective candidates for new generation wide-bandgap and large-voltage applications, such as smart grid, electric vehicles and wind power systems. However, due to structural CTE mismatches and harsh thermal conditions, the die-attachments in SiC power devices becomes a fundamental and critical issue for the durability and long-term reliability of power electronics devices. In this paper, a computational method based on fracture phase-field modeling is implemented to analyze the thermal effects and fracture behavior of chip attachments under power cycling conditions. Fracture phase-field modeling is applied to understand the fracture behavior of chip attachments, which play crucial roles in mechanical supporting and thermo-electrical connections of SiC power devices. Utilizing UMAT and UEL in Abaqus, different power cycling conditions were performed to investigate the effects of power density and switching frequency on crack extension rate and crack morphology. Some promising results were obtained to guide the power cycling failure analysis of SiC power devices in practical applications.