EMI Evaluation of a SiC MOSFET Module with Organic DBC Substrate

Abstract

This work evaluates the electromagnetic interference (EMI) of a silicon carbide (SiC) MOSFET multi-chip power module (MCPM) with emerging organic direct bonded copper (ODBC) substrates. The thin, ductile organic insulator in ODBC substrates allows for thick copper to be used. The thick Cu enables higher current capacity and improved heat spreading. However, the thin dielectric increases capacitive coupling within the power module. This work evaluates the electromagnetic interference (EMI) characteristics of a SiC half-bridge module using ODBC substrates, and compares them to a commercial SiC module using standard ceramic DBC substrates. To mitigate the effects of the ODBC module’s increased capacitive coupling, a common-mode equivalent model (CEM) is leveraged to design a unique substrate layout that enables cancellation of leakage current through the baseplate. The proposed method shows that the ODBC module can achieve over 20 dB lower baseplate leakage current compared to a commercial power module for a single-phase half-bridge inverter implementation.