Investigating the Properties of a New Vertical 4H-SiC Photoconductive Semiconductor Switch With a Double-Side Epitaxial Structure

In this work, a new vertical vanadium-compensated semi-insulating 4H silicon carbide (VCSI 4H-SiC) photoconductive semiconductor switch (PCSS) with the heavily doped interlayers between electrodes and substrate is proposed to further enhance the operating electric field. For 532 nm, 10-ns laser excitation, the numerical simulation was conducted to characterize the static and dynamic electrical performance of the proposed device. The simulation results confirm that the introduced heavily doped interlayers effectively homogenize the internal electric field distribution within the 4H-SiC substrate and, more notably, reduce the dark-state peak electric field by as much as 93.91% relative to the device without interlayers, exhibiting superior high-voltage characteristics. Experimental results demonstrate that the proposed device achieves a maximum operating electric field of 300 kV/cm, representing a 50%–87.5% enhancement over existing PCSSs.