SiC MOSFETs as Enabler for the future ePowertrain and its behaviour under Short Circuit Condition

摘要

Silicon Carbide (SiC) components have been used for a number of years in industrial applications and now are progressively entering the automotive segment. The first devices of this wide-bandgap material to be used in vehicle applications were SiC diodes in on-board charger (OBC) applications. The excellent SiC diode switching performance is ideal for the freewheeling path in the power factor correction stages. The market for automotive grade SiC components is showing impressive growth aligned to the rise in electric vehicles with SiC MOSFETs being used in traction inverters as well as OBC or DC-DC converter applications. This paper explains the significant advantages that wide-bandgap technologies have compared to well establish Si technologies. This applies especially for the total cost of ownership approach, not considering the single device only but the complete application or interaction between different components. When a new semiconductor material is introduced into the automotive sector, the stringent qualification requirements mean that a special focus is needed on the manufacturing strategy. This paper also describes a manufacturing strategy designed to serve the automotive market, the key reliability factors and how improvements have been achieved. As power density of the new technology compared with Si devices is strongly increasing, simulation approaches have been introduced to characterize MOSFETs under short circuit condition to ex-plain the failure mechanism under such harsh applications conditions.