Experimental and Simulation Characterization of Semi-Insulating 6H SIC Photoconductive Switch for Pulsed Power Applications

High resistivity SiC has been shown to be a viable PCSS material [1]. High breakdown field, extreme thermal stability, wide energy band-gap, crystal robustness, and large electron saturation velocity are likely to make devices made from SiC more reliable under extreme operating conditions [2]. Because of its limited use this far, there is a need to study and characterize a SiC PCSS as a viable component of a circuitry for high power generator. In this presentation we discuss the characteristics of a compact SiC PCSS being tested for potential high power applications at the Electrical and Computer Engineering (ECE) Department, University of Missouri at Columbia (UMC). Specifically we look into the carrier transport properties of high resistivity 6H SiC in light of its usefulness as a PCSS for high power applications. We discuss the material properties, role of traps and propose designs for high power linear mode applications. We also describe the semi-conductor physics modeling of a SI 6H SiC switches in high electric field configuration. The reasons for the breakdown of the switch are discussed. The model results of heavily doped p+ regions along cathode on carrier injection, leakage current, and voltage hold off is discussed The modeling of the transverse injection of optical closure energy is discussed along with the experimental results. The changes in the photoconductivity with below band gap illumination are shown.