I. Introduction
Emerging medium-voltage (MV) silicon carbide (SiC) MOSFETs have potential to replace their silicon counterparts in grid applications because of their better Figure-of- Merit [1]–[4]. However, before they can be adopted in power stations, innovative packaging solutions for these devices have to be developed. One needed innovation is for better insulation of the MV wide bandgap device packages [3], [5]. In a typical MV power device package, a direct-bond copper (DBC) substrate and a silicone gel for insulating the device are under high electric field (E-field) intensities. The field stress is the highest [6], [7] at the meeting locations of three different materials in the package, such as metal pad, ceramic, and silicone gel. These locations are referred to as triple points (TPs). Since TPs are also the preferred sites for trapping air bubbles inside the silicone gel, partial discharges (PDs) often take place there, accelerating the aging and failure of the insulation [3], [8].