N-channel JFET integrated circuits were fabricated in 6H silicon carbide, a wide-bandgap semiconductor capable of operation at extremely high temperatures, to support applications in high-temperature sensing and control commonly found in systems that consume or generate large quantities of energy. The JFETs were successfully modeled, and hybrid amplifiers were constructed using SiC differential pairs and silicon active/passive components to provide a high-temperature sensor interface circuit requiring minimal SiC integration. Fully integrated, differential amplifiers were designed, fabricated, and tested. A two-stage amplifier with current-source loads and common-mode feedback in the 1st-stage, has a voltage gain of 69 dB at 576°C, with just 3.6 dB gain-variation from 25 to 576°C. High-performance, integrated logic circuits were also developed. The inverter has excellent dc characteristics with a gain > −20 up to 500°C. NAND/NOR logic circuits were tested dynamically and perform well at temperatures up to 550°C.
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