This thesis presents the development of a double-side cooled 3.3 kV, 100 A SiC MOSFET phase-leg power module for heavy-duty traction applications. Parasitic extraction and thermal simulations of the module showed a parasitic inductance of 2.89 nH and junction temperature of 108.3 °C at a heat flux of 156 W/cm² under a typical water-cooling condition. Electric field simulations identified high electric field stress at the module's outer surface edges exposed to air, posing a risk for partial discharge. To mitigate this risk, a solution that involves covering the critical point in an epoxy was proposed, analyzed, and validated through partial discharge inception voltage tests. Steps for fabricating the module are presented. Static electrical characterization of the fabricated module showed an average on-resistance of 31 mΩ and an average leakage current of 356 nA at VDS of 3 kV, which are similar to those of the unpackaged devices. The module with a double-side cooling design achieved an exceptional power density of 116.6 kW/cm³, more than twice that of any single-side cooled 3.3 kV SiC module. This makes it highly suitable for next-generation electric transportation systems that require high power density and efficient thermal management, such as electric trucks, railways, and eVTOL aircraft. / Master of Science / This thesis presents the development of a highly efficient and compact power module designed for electric vehicles and other high power applications. By utilizing advanced silicon carbide technology and double-side cooling structure, the module achieves outstanding performance, making it ideal for heavy-duty uses such as electric trucks, railways, and eVTOL aircraft. The module operates at 3.3 kV and 100 A, with low electrical losses and excellent thermal management. Extensive simulations and testing demonstrated that the module significantly reduced unwanted electrical effects and maintained a stable temperature under high power conditions. An epoxy coating was applied to critical areas to prevent electrical discharge, enhancing the module's reliability. The fabrication process incorporated packaging techniques like silver-sintering for attaching the semiconductor chips and other components, resulting in strong and reliable connections. Static tests confirmed that the electrical performance of the packaged power module maintained consistently high efficiency compared with the bare chips. Overall, this double-side cooled power module offers more than twice the power density of traditional designs, paving the way for the development of future electric vehicle traction systems that require high power density and efficient cooling.