Transient and steady state study of a rear-illuminated 6H-SiC Photoconductive Semiconductor Switch

In this paper characteristics of a linear, 6H-SiC photoconductive semiconductor switch are presented. The vanadium-doped semi-insulated 6H-SiC PCSS device is designed in a back-triggered, radial switch structure. For this purpose, three-dimensional (3D) device modeling tool was used to model and test the optically initiated 6H-SiC switch. Dark I–V characteristic results show that newly proposed rear-illuminated radial switch structure extends the blocking voltage by reducing the peak electric fields near electrodes. Also this radial structure has higher dark resistance as compared to the previous 6H-SiC PCSS experimental results. The ON-state characteristics of vanadium compensated 6H-SiC switch demonstrate that dynamic switch resistance, another important switching parameter, is lower than previous semiconductor switches with opposing electrodes. This paper evaluates photoconductivity tests for different laser wavelengths and different substrate thicknesses. Also Transient characteristics of PCSS for two different type of compensation have been reported. The photoconductivity results are discussed showing the advantages and disadvantages of SDDA and DDSA compensated materials.