A New Characterization Technique for Extracting Parasitic Inductances of SiC Power MOSFETs in Discrete and Module Packages Based on Two-Port S-Parameters Measurement

The parasitic inductances of silicon carbide (SiC) power mosfets have a major influence on their operation and circuit performance. They incur negative effects such as switching oscillations, power losses, and electromagnetic interference noise. This paper introduces a new technique to accurately characterize the parasitic inductances of SiC power mosfets in both discrete packages and power modules based on two-port S-parameters measurement. By treating a power mosfet as a two-port network, we obtain the scattering (S) and impedance (Z) parameters from network analyzer measurement. These parameters, through detailed network analysis, provide more accurate values of the internal parasitic inductances than the commonly used single-port impedance measurement technique. The new approach is first verified with high-frequency circuit simulation and then applied in the case study of SiC power mosfets in a TO-247 discrete package and a half-bridge power module. In addition, a number of silicon power mosfets and IGBTs in TO-247, TO-220, D ² PAK, DPAK, and SO-8 packages are also characterized for comparison. A comparison between the characterization results from the new two-port and the prior art one-port methods reveals a significant difference ranging from 12.6% to 93.9%.