Power Module Design with Chip-Level Series-Connected SiC MOSFETs

Series connection of Silicon Carbide (SiC) Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) is a viable solution to design switches for voltages that are not yet commercially available or limited for single-die devices. However, the stray inductance in the current commutation loop is larger than a single high-voltage (HV) device, due to the electrical connections of the series-connected SiC MOSFETs. Thus, instead of serializing several discrete packaged devices or internally in a half-bridge module, which introduces significant stray inductance, a power module with chip-level series-connected SiC MOSFETs is designed and tested. Two 1.2kV-rated SiC MOSFETs dies are connected in series to form a 2.4kV switch and decoupling capacitors are integrated inside the module to decouple the stray inductance of the terminals. Using the proposed module layout design, voltage balancing of 3% and switching speeds of 25.2kV/µs have been measured experimentally.