A full-circuit simulation model of silicon carbide Drift Step Recovery Diode (DSRD) and Diode Avalanche Shaper (DAS) was built based on Sentaurus. By use of simulation, this paper investigates the capability of silicon carbide plasma devices in pulse sharpening and explains the mechanism of pulse sharpening achieved by these two devices through the plasma concentration distribution inside the devices. With the help of a silicon carbide DSRD, it is possible to reduce the pulse front of voltage pulses with peaks in excess of kilovolts to 300 ps. The combination of the silicon carbide DSRD and DAS can output voltage pulses with a pulse front of 35 ps and a peak of more than two kilovolts. Simulations and experiments show that when the trigger pulse is matched to the silicon carbide DAS, fast turn-on and turn-off can be achieved. Thanks to the magical phenomenon of silicon carbide DAS, it can reduce the half-height width of pulses with peak values above 2 kV to the order of 100 ps. Through spectrum analysis, it is found that after the pulse is sharpened by DAS, its -30 dB spectral width is expanded by a factor of 37 to 7.4 GHz.