Improved performance of SiC MESFETs using double-recessed structure

A double recessed SiC MESFET was proposed and its electrical performances were studied by numerical simulation. Our simulated results showed that the saturation current of the double recessed structure is about 77% larger than that of the conventional structure. However, their threshold voltages are comparable and are −9.2 and −8.4 V for the double recessed and conventional structure, respectively. The output power density of the double recessed structure is about 37.5% larger than that of the conventional structure though its breakdown voltage is lower. The cut-off frequency (fT) and the maximum oscillation frequency (fmax) of the double recessed structure are 15.3 and 70.6 GHz, respectively, which are higher than that of the conventional structure. Therefore, the double recessed 4H-SiC MESFET has superior DC and RF performances compared to the similar device based on the conventional structure.