Design of a 2.4 kV Half-Bridge Power Module With Chip-Level Series-Connected SiC MOSFETs

Abstract

Series connection of silicon carbide (SiC) metal-oxide–semiconductor field effect transistors (MOSFETs) is a viable solution to reach blocking voltages that are not yet commercially available or limited for single-chip devices. Typically, serialization is realized with discrete packaged devices or power modules. However, serializing several of these packaged Silicon Carbide (SiC) MOSFET devices increases the stray inductance in the power loop compared to a single high-voltage (HV) device, due to the electrical connections of the devices. This paper proposes a design of a half-bridge power module with chip-level series-connection SiC MOSFET, which are accommodated on a single direct bond copper (DBC) layout. In order to demonstrate the feasibility of this approach, a DBC layout accommodating two series-connected $1.2\mathrm{kV}$ SiC MOSFET chips to form a $2.4\mathrm{kV}$ switch has been designed. Integrated inside the module are decoupling capacitors to mitigate high-frequency current and voltage oscillations. The power module's inductive layout is characterized and presented in terms of finite element method simulations and measurements. The HV isolation capability of the proposed power module in terms of the partial discharge-limit, was also measured. Finally, the switching performance of the series-connected chips is presented experimentally both in a double pulse test and under continuous operation in a synchronous buck converter, both at a blocking voltage of $1.5\mathrm{kV}$.