System Analysis and PHM Methods for Power Devices Based on Physics-of-Failure

Power devices are widely used in power electronics, automotive, aerospace fields. The failures of power devices will lower the system efficiency, and further more cause the catastrophic failure of the system. Therefore, the application of prognostics and health management (PHM) on power devices is greatly significant. This paper takes VDMOS as a research object. System definition, loads analysis, failure mode, mechanism and effect analysis (FMMEA) of VDMOS devices are firstly conducted, and the dominant failure mechanisms are identified as TDDB, SEGR, bonding fatigue and Kirkendall effect. Then, the failure precursors of VDMOS are identified for each dominant failure mechanism. The physics-of-failure (PoF) models of each dominant failure mechanism can be constructed consequently. Finally, from the application point of view, the implementation of online-monitoring and prognostics for VDMOS based on PoF is presented.