Microwave power MESFET on 4H-SiC

We present static and microwave characterization of NIESFETs processed on n(+) 4H-SiC wafers supplied by Cree Research. An eight-level technology including airbridge interconnections has been performed. Transistors with total gate width up to 6 mm and 1.2 mu m gate length optically designed are obtained. High breakdown voltage (up to 140 V) and high drain current (up to 0.7 A) show the high power capability of the transistors. RF characterization was performed. Because of the use of a conductive substrate, parasitic capacitances account for the relatively low values of f(T) and f(max) (4 and 9 GHz, respectively). Power measurements were carried out at 1 and 2 GHz in cw. Output powers up to 1.7 W mm(-1) were measured with a power added efficiency of 37% at 2 GHz. (C) 1997 Elsevier Science S.A.