Analysis of Stress Wave Characteristics in SiC MOSFETs with Solder Layer Voids

The stress waves generated during the switching process of power devices are crucial for monitoring their status and assessing failures. This paper summarizes research methods for stress waves in power devices and constructs a stress wave testing platform. A failure type of solder voids in SiC MOSFET power modules is designed and module packaging is completed. The characteristics of stress waves in SiC MOSFET power modules are extracted, indicating that stress waves consist of high-frequency and low-frequency components with specific frequency distribution patterns. The stress wave characteristics of SiC MOSFET power modules with solder voids are studied through comparative experiments. The results demonstrate that solder voids cause delays in stress wave transmission and induce attenuation in the stress wave spectrum across most frequency ranges.