Electrothermal Considerations for Power Cycling in SiC Technologies

From the perspective of an application engineer, power semiconductor devices over the course of their mission profile will undergo a defined number of operation cycles depending on the switching frequency, variations of the load current, supply voltage as well as the thermal impedance characteristics of the packaging. SiC devices and modules are now widely and commercially available and it is necessary to understand how they perform under power cycling conditions. Different device technologies through their different architectures will exhibit different temperature coefficients and based on the respective internal physics of the device will produce different temperature cycle characteristics. 600 V SiC Schottky diodes and silicon PiN diodes have been studied in this paper with the aim of understanding how the different electrical properties of the devices affect the temperature profile and power cycling. One of the main requirements of power cycling is the use of temperature sensitive electrical parameters (TSEPs) for the estimation of the operating junction temperature which is a subject of interest for both power cycling and condition monitoring. This paper discusses a number of factors that must be taken into consideration when power cycling different technologies, underlining the limitations of the packaging technology, the differences between technologies and the challenges of using alternative setups for power cycling.