Preparation and Properties of Lateral Contact Structure SiC Photoconductive Semiconductor Switches

A series of lateral structural photoconductive semiconductor switches (PCSS) were fabricated on V-doped semi-insulating 6H-SiC substrate with the Ni/Au contacts. These PCSS were measured with different bias voltages, excitation energies and excitation wavelengths. The photoelectric absorption effect and photoelectric response of SiC PCSS were investigated. It is found that the absorption coefficient is between 0.601 and 0.692 mm–1 for semi-insulating 6H-SiC substrate when it is excited by 532 nm laser, and the corresponding pulse signal is much smaller than that excited by 1064 nm laser. Nanosecond-pulse signal is obtained for 6H-SiC PCSS excited by 532 nm laser. The peak current flowing through the switch is increased with increasing the bias voltage and excitation energy, while it is decreased with the increase in substrate thickness.