Failure Phenomenon of 4H-SiC Schottky Barrier Diode Under Thermal Shock Reliability Test

The temperature reliability of silicon carbide power devices has long been a concern. The thermal shock test is an effective test method that simulates the ambient temperature swings to examine its reliability. In this paper, 1200 V / 20 A 4H-SiC Schottky barrier diodes were selected for thermal shock test (TST). The influence of thermal and cold environment on the electrical characteristics of SiC devices is analyzed, and a conduction failure phenomenon is found. Then, the failure phenomenon is analyzed theoretically by scanning acoustic microscope (SAM), wire bonding pull tests, the coefficient of thermal expansion of different parts of the device, and so on. Finally, based on Comsol simulation software, multi-physical field simulation is carried out to simulate the thermal stress distribution and solder joint displacement changes of the devices under rapid temperature variations, and the simulation results were in good agreement with the experimental analysis.