Effect of Donor–Acceptor Compensation on Transient Performance of Vanadium-Doped SiC Photoconductive Switches Using 532-nm Laser

Transient performance of vanadium-compensated semi-insulating 4H-silicon carbide (SiC) photoconductive semiconductor switches (PCSSs) is investigated through experimental testing and simulation under 532-nm laser triggering. Two types of impurity compensation (vanadium/nitrogen/boron) are presented: shallow-donor deep-acceptor (SDDA) and deep-donor shallow-acceptor (DDSA). The internal physical mechanism model is built to simulate the observed difference in device performance. Three vertical PCSS devices with varying doping concentrations are fabricated and tested under light peak power of several hundreds of kilowatts and operational voltages ranging from 0.5 to 10 kV. The maximum electrical peak power achieved by the SDDA device (a peak current of ~40 A) is higher than that of DDSA devices (a peak current of ~15 A). DDSA devices experienced bulk breakdown at 5 and 4 kV. The SDDA device exhibits superior photoelectric efficiency compared to DDSA devices due to the higher electron mobility. Moreover, the long tail in the photocurrent response of DDSA device is attributed to the presence of B hole traps (HTs), which leads to bulk breakdown and weak frequency response characteristics.