Condition monitoring indicators for Si and SiC power modules

Abstract

The reliability of power modules plays a crucial role in developing safer and smarter generations of electric vehicles. Condition monitoring represents a possible solution to predict the possible occurrence of catastrophic failures and avoid unexpected breakdowns. More specifically, power modules for inverter applications are a technology requiring condition monitoring indicators to detect ongoing degradation mechanisms. In this work, both silicon IGBT and silicon carbide MOSFET power modules are thermally stressed through the application of a pulsed direct current until reaching end-of-life limits. As a result, two main failure mechanisms occurring at package level are observed: chip solder degradation and bond-wire damages. In addition, on-state voltage, junction temperature, and thermal resistance are measured during the power cycling as parameters to monitor the device states of health. After the test, the chip solder conditions and bond-wires robustness are checked through scanning acoustic microscope images and optical inspections, respectively. The novelty of this work lies in refining and comparing health indicators for silicon and silicon carbide power modules.