Calibration methods and power cycling of double-side cooled SiC MOSFET power modules

Abstract

Reliability analysis depends heavily on accurate measurements of junction temperatures for power semiconductors. It forms the foundation for precise reliability tests such as power cycling tests. One of the most established methods for junction temperature measurement in MOSFETs is the VSD(T) method. With the introduction of new module configurations such as the DSC (double-side cooled) module with cooling on both sides, conventional calibration methods for single side cooling require a critical review regarding their applicability. This article will highlight various calibration options and analyse them in regard to sensitivity and reproducibility for DSC modules. Subsequently, the most promising methods are evaluated experimentally. It was found that by heating the modules on both sides, a better temperature uniformity can be achieved than from single side heating alone. This allows to apply the VSD(T) method on DSC modules also during power cycling. A power cycling test with in situ mechanical force measurement was conducted to verify the results.