Development of high-frequency SiC-MESFETs

With rapid growth of mobile communications represented by portable telephones, further increases in the output of high-frequency power transistors for the base stations are required. Also, in the fields of satellite communications and radar, realization of high-power transistors replacing electron tubes such as TWTs and magnetrons is desirable for size reduction, weight reduction, and extension of transmitter life. As a transistor meeting such needs, the metal semiconductor field effect transistor (MESFET) based on silicon carbide (SiC) has been attracting attention. SiC is superior in material characteristics such as the electric breakdown field and thermal conductivity and is expected theoretically to provide high power density as a high-frequency transistor. To date, higher output power density than MESFETs based on Si and GaAs of the same size has been achieved, including an output power density of 4.2 W/mm at 1 GHz. In this paper, the high-frequency characteristics of the tested SiC high-frequency MESFET are presented and trends in research on improvement of the high-frequency characteristics are described. (C) 2003 Wiley Periodicals, Inc.