Design and Simulation of Silicon-Based EFI Switches Using Substrate-Integrated Thyristors: A Cost-Effective Alternative to SiC

This study presents the design and simulation of two silicon-based explosive foil initiator (EFI) switches using the Synopsys TCAD platform. One design utilizes a lightly doped n-type silicon wafer, while the other employs a lightly doped p-type silicon wafer. Unlike conventional designs in the literature, this study adopts the substrate wafer itself as the thyristor's drift layer, representing a key scientific contribution. This approach serves as an alternative to growing sufficiently thick epitaxial layers to achieve high breakdown voltage levels. While recent EFI switch designs focus on silicon carbide (SiC) due to its higher bandgap energy, the proposed designs utilize silicon, offering a more cost-effective alternative for thyristor-based EFI applications. The study aims to optimize critical design parameters, including layer dimensions and doping concentrations. Simulation results are compared with both similar EFI designs from the literature and a commercial product, focusing on key performance metrics such as di/dt , breakdown voltage, and turn-on delay. The findings indicate that the proposed designs achieve comparable or even superior performance. The primary drawback of this approach is the increased device thickness compared to traditional SiC-based designs. Additionally, the study explores the impact of doping concentrations, layer dimensions and placements, as well as layout configurations (square vs. cylindrical) on device performance, marking another significant contribution. Given the limited research in this field, the results of this study will serve as a valuable resource for researchers developing high-energy switching devices.