A New Method of Accurately Measuring Photoconductive Performance of 4H-SiC Photoconductive Switches

A new method of accurately measuring the photoconductive performance of photoconductive semiconductor switch (PCSS) was proposed. By this method, we succeeded extracting the photoconductivity of 4H-SiC substrate free from the obstruction of parasitic inductance in the test circuit. Photoconductive performance of the PCSS was precisely measured, where a maximum ON-state photoconductivity of 6.26\,\,(\Omega \cdot \text {m})^{-1} , a minimum ON-state resistivity of 0.16~\Omega \cdot \text {m} , and an accurate minimum resistance of 1.71~\Omega were obtained for SiC substrate. The quantitative relationship between the ON-state resistance and the reciprocal of area of laser trigger region was proved. The performance of PCSSs can be continuously adjusted to adapt different application requirements just by changing the area of laser excitation region.