4H-SiC MESFET with 2.8 W/mm power density at 1.8 GHz

Abstract

MESFET's were fabricated using 4H-SiC substrates and epitaxy. The D.C., S-parameter, and output power characteristics of the 0.7 μm gate length, 332 μm gate width MESFET's were measured. At /spl nu//sub ds/=25 V the current density was about 300 mA/mm and the maximum transconductance was in the range of 38-42 mS/mm. The device had 9.3 dB gain at 5 GHz and f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> =12.9 GHz. At V/sub ds/=54 V the power density was 2.8 W/mm with a power added efficiency=12.7%.