SIC FOR MICROWAVE-POWER TRANSISTORS

The advantages of SiC for high power, microwave devices are discussed. The design considerations, fabrication; and experimental results are described for SiC MESFETs and SITs. The highest reported f(max) for a 0.5 mu m MESFET using semi-insulating 4H-SiC is 42 GHz. These devices also showed a small signal gain of 5.1 dB at 20 GHz. Other 4H-SiC MESF ETs have shown a power density of 3.3 W/mm at 850 MHz. The largest SiC power transistor reported is a 450 W SIT measured at 600 MHz. The pow er output density of this SIT is 2.5 times higher than that of compara ble silicon devices. SITs have been designed to operate as high as 3.0 GHz. with a 3 cm periphery part delivering 38 W of output power.