High Performance 4H-SiC MESFETs with a Source Field Plated Structure

A new structure of 4H-SiC MESFET based on the source field plate technology is proposed in this paper. The source field plate has been applied not only to improve the breakdown voltage, but also to eliminate the drawback of low gain characteristics relatively resulted from additional feedback capacitance associated with the field plate electrode. The off-state breakdown voltage was significantly improved by employing source field plate electrode, and the highest of 203V was obtained. As compared to the conventional structures, the MESFETs with source field plate show an approximately 41% decrease in gate-to-drain capacitance, which is responsible for the 2.2dB gain improvement at 2GHz. Therefore, the 4H-SiC MESFETs with source field plate have superior DC and RF performances compared to the similar devices based on the conventional structure.