Development of high-power SiC MESFETs for microwave applications

SiC MESFETs were fabricated using in-house grown epitaxial structures on semi-insulating 4H-SiC substrates. Field-plate technique was used to enhance power performance. DC and small-signal characteristics were measured for small gate-periphery devices. Packaged 20-mm SiC MESFET transistors were demonstrated with a saturated power 80 W and 44% drain efficiency with the pulsed condition at a duty cycle of 10% and 300 musec pulse width. A SiC MESFET amplifier was developed for S-band operations consisting of internally partial- matched SiC MESFETs. The amplifier delivered a peak power of 280 W under pulsed operation with 8.6 dB power gain at 2 GHz and 65 V drain voltage.