Investigating the Properties of a New Lateral 4H-SiC Photoconductive Semiconductor Switch With a Stacked Structure

In this work, a new lateral photoconductive semiconductor switch (PCSS) based on high purity 4H Silicon Carbide (4H-SiC) was presented composed of a stack structure with gallium nitride epitaxial layer being grown between the electrodes. Using the Sentaurus TCAD software package, different numbers, widths, and depths of the GaN epitaxial layers were simulated. From our analysis, it was found that the output current of the photoconductor switch with the stacked structure was higher under the same conditions in the case of specific stack cells. In particular, the carriers' transmission and distribution properties were changed. More specifically, a stacked structured PCSS with a width of 250 um, a depth of 1 um, and 10 stacked cells was also fabricated. A circuit with a 50Q load resistor was also used to test the performance of PCSS, and the switch was triggered by Nd:YAG 355-nm laser (18 ns full-width). From the extracted results, it was demonstrated that compared with the PCSS without the stack structure, the laser saturation energy required by the PCSS with the stack structure was reduced by 20%. When the laser energy was saturated, the on-resistance of the PCSS with stack structure was 37.3% less than that of the PCSS without stack structure when the applied bias voltage was 10 kV.