Microwave power of S-band 20mm SiC MESFETs

Silicon carbide (SiC) MESFETs were fabricated by employing the common recess gate etching process using home-grown epi structures. The damage to the gate region during etching process was eliminated by using sacrificed oxidation and wet etching processes. An ion implant-isolation technique was applied to realize the active device area to decrease the height of the device mesa. A field-plate structure was used to achieve higher breakdown voltage and higher power density. Excellent ohmic and Schottky contact properties were achieved. Packaged 20-mm SiC MESFET demonstrates an output power of 96 W with 33.6% PAE (power added efficiency) and 10 dB small signal gain at 2 GHz under pulse operation. When operated at continuous wave (CW), the same devices produced an output power of 41 W (~2.05 W/mm) with 44.8% PAE and 6.4 dB linear gain.