Study of Silicon Carbide Power MOSFETs Behaviour in Out-of-SOA Conditions

The need for efficient conversion and control of electrical power in many application areas has rapidly increased the demand for power devices with better and better performances. In order to go beyond the limit imposed by Silicon devices, there has always been a great interest for new materials. In recent years, Silicon Carbide Power devices, mainly power diodes and MOSFETs, have become commercially available and have begun to replace their Silicon counterpart in many application areas. The reason lays in some superior material properties that allow developing higher efficient power systems. Nevertheless, a wider spread of these devices could not be achieved without a deep analysis of the elements that might affect their reliability. The current work deals with the study of SiC Power MOSFETs reliability, with particular focus on short-circuit operation. To achieve this purpose, wide set of experiments has been carried out on commercially available devices, providing both electrical and thermal characterization. Alongside experimental evidences, TCAD simulations have been used to get a full understanding of the inner physical failure dynamics. Eventually, it has been possible to give explanation about SiC Power MOSFETs failure mechanisms. In particular, two different phenomena might occur and both are related to temperature increase inside the device.