A new phenomenon in semi-insulating 4H-SiC photoconductive semiconductor switches

A new oscillational phenomenon has been found in high-biased semi-insulating (SI) 4H-SiC photoconductive semiconductor switches (PCSSs) with high densities of vanadiumand nitrogendopants, and this oscillational phenomenon has no relationshipwith the laser wavelength, bias voltage, the charge capacitor, and the shape/size of the 4H-SiC PCSS. This paper shows that the photo activated charge domain theory in SI GaAs PCSS may explain this phenomenon. Due to the high densities of vanadium and nitrogen dopants, the intervalley scattering may occur in the 4H-SiC PCSS, and the space charge field region will appear in the 4H-SiC PCSS for the electrons accumulation. This region looks upon an equivalent capacitor, when the accumulation of the electrons is over, the equivalent capacitor will discharge, and the oscillational phenomenon appears.