Design Rules for Paralleling of Silicon Carbide Power MOSFETs

Increasing the capability of a power switch by using several individual MOSFETs connected in parallel is a common practice with silicon semiconductor devices. This paper deals with the results of an investigation of the issues linked to paralleling the Silicon Carbide (SiC) MOSFETs. Based on the experimental validation of paralleled discrete devices the investigation focuses on the main electrical parameters affecting the performance of the paralleled switch. Moreover the influence of circuit mismatch on paralleling SiC MOSFETs is investigated as well as the impact of the "Kelvin source" connection that is tailored to mitigate the effects of not fully symmetric layout. A dedicated test vehicle has been developed to include all these aspects in the evaluation and carry out the tests on a switch element rated up to 300 A.