Effect of punch through factor on the breakdown characteristics of 4H-SiC IMPATT diode

Computer simulation has been carried out to investigate the effect of punch through on the breakdown properties such as peak electric field, breakdown voltage and DC-to-RF conversion efficiency of 4H p⁺nn⁺ SiC Impatts. The effect of mobile space charge and diffusion has been incorporated in the analysis. The results indicate increase of junction field at breakdown with sharp decrease of breakdown voltage with increasing punch through factors. It has also been observed that the diode exhibits a space charge induced positive resistance which decreases at higher doping levels. A comparative study reveals that higher DC-to-RF conversion efficiency and higher breakdown voltage can be obtained from 4H-SiC Impatts than from Si Impatts.