Comparison of Medium-Voltage Oscilloscope Probes for Evaluating Silicon-Carbide Multi-Chip Power Modules

Continuous improvements in silicon carbide (SiC) technology has led to the development of medium-voltage (MV) SiC MOSFETs that support significantly higher edge rates and operating frequencies than those supported by MV silicon technology. Before these MV semiconductors can reach large-scale adoption, their behavior must be accurately characterized and modeled. This characterization process requires high-fidelity time-domain measurements to capture the high-frequency behavior of these semiconductors. Many publications discuss the challenges associated with performing such measurements for low-voltage (LV) SiC MOSFETs operating below 1.2 kV. The challenges associated with accurately characterizing MV SiC MOSFETs have received less treatment in the literature. The LV challenges are heightened at MV since probe attenuation is increased and probe bandwidth is decreased. This paper provides a detailed comparison of commercially available MV oscilloscope voltage probes. A subset of the available MV voltage probes is compared experimentally up to 5.0 kV and the results are analyzed using a simple oscilloscope probe model. Finally, the relative performance of the probes under consideration is discussed, and guidelines are provided for selecting a suitable MV oscilloscope voltage probe.