I. Introduction
Advances in medium-voltage (MV) wide bandgap (WBG) power semiconductor devices present power electronics expansion opportunities in grid applications. For example, using these devices in transformers and circuit breakers for a high-voltage, direct current (HVDC) grid can significantly reduce the size of the grid's substations. [1]–[6]. However, before the MV WBG devices can be widely accepted in the grid applications, innovative packaging solutions of these devices in modules are needed to address the trade-off between heat dissipation and insulation demand. The high blocking voltage and reduced size of MV WBG power modules require a more stringent insulation design [7]–[9]. One way to meet the insulation demand is to increase the ceramic thickness [10] of the device interconnection substrate for reducing the nominal electric field (E-field), or stacking the substrates [11], [12] to reshape the E-field. However, the substrate-thickening approaches increase the junction-to-case thermal resistance, reducing the module heat dissipation. This is particularly problematic for MV WBG devices because they are expected to handle higher heat flux due to the higher rated current density than their silicon counterparts [13].