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Silicon-on-insulator MESFETs have been manufactured using a commercial SOI CMOS process and their electrical characteristics measured from room temperature up to 200° C. No modifications were made to the CMOS process flow. The prototype devices use a CoSi 2 gate material and the gate current follows the expected Shottky diode behavior. At room temperature a 0.6 µm gate length device has a threshold voltage of -0.8 V with an offstate drain current of approximately 5 nA. The device shows an attractive family of I-V curves up to 200° C. For higher temperatures the reverse diode current makes it hard to switch the device off. Numerical simulations of a similar device with a higher barrier height PtSi gate show reasonable behavior up to 300° C.

Metal Semiconductor Field Effect Transistors fabricated using compound semiconductor materials have important applications in high-speed/low-noise communication systems. However, their integration densities are low compared to silicon technologies, and it is difficult to combine them with conventional CMOS for single-chip, mixed-signal circuit applications. In this paper we describe how silicon-on-insulator MESFETs can be fabricated alongside conventional MOSFETs using a commercially available silicon-on-insulator foundry. The process flow for the integrated MOSFETS and MESFETs is presented. Measurements from MESFETs fabricated using a commercial foundry demonstrate good depletion-mode device operation. The measured data confirms a square-law behavior for the saturated drain current, which can be reproduced using readily available MESFET models for Spice circuit simulation. The Spice model is applied to a simple differential-pair amplifier and the modeled results compared to measured data.

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