Thermal behaviour evolution of an IGBT module after aging measured by thermoreflectance

In this paper, we propose to study the thermal mapping evolution of the Insulated gate bipolar transistor (IGBT) emitter metallization after aging by thermoreflectance. Thermoreflectance measurements were done in static regime before and after aging by DC power cycling. The aim of this study is to observe the change in thermal behaviour at the cell level due to power cycling aging. Preliminary results indicate that a pixel-by-pixel calibration which takes into account the topography and chemical changes of the metallization is essential to eliminate artefacts in thermal images and to allow to follow metallization thermal evolution with aging.