Mission-Profile-Based Lifetime study for SiC Module Chips using Graphene Films

Abstract

This work studies a lifetime comparison of silicon carbide (SiC) MOSFET's chips in a SiC power module when incorporating and not incorporating graphene assembled films in the packaging of the SiC module. To model the investigated SiC power module as close as possible to a real module, two experimental analyses comprising of a scanning electron microscopy (SEM)as well as an energy spreading X-Ray spectroscopy (EDS) are conducted on the module to identify the material layers and the respective thicknesses. The Worldwide Harmonized Light Vehicles Test Cycle (WLTC) is used as a mission profile for lifetime comparisons. The analysis reveals that, Utilizing the graphene assembled films as a layer in the silicon carbide (SiC) module demonstrates an improved heat spreading through the different layers inside the module. This leads to a lower thermal stress as well as a lower accumulated damage on the SiC MOSFET's chips for an applied worst condition power loss per chip. Therefore, a higher lifetime of 9.3% per chip is achieved when adding the graphene layer in the module compared to that of not using graphene layer in the module packaging.