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Development of silicon carbide operational amplifier offers an attractive alternative building block for the replacement of silicon and silicon-on-insulator analog circuits in harsh environment applications. NMOS-based enhancement mode silicon carbide device technology was utilized to demonstrate feasibility of operational amplifiers for use in harsh environment applications. This study reports on the results of characterization of operational amplifiers at room temperature and high temperatures up to 350°C. The development of high temperature packaging techniques enabled assembly of a functional oscillator board tested up to 350°C. A test fixture with high temperature sockets enabling quick swap of operational amplifiers is also discussed as an important tool in high temperature electronics research and development.

MOSFET-based integrated circuits were fabricated on silicon carbide (SiC) substrates. SiC devices can operate at much higher temperatures than current semiconductor devices. Simple circuit components including operational amplifiers and common source amplifiers were fabricated and tested at room temperature and at 300°C. The common source amplifier displayed gain of 7.6 at room temperature and 6.8 at 300°C. The operational amplifier was tested for small signal open loop gain at 1kHz, measuring 60 dB at room temperature and 57 dB at 300°C. Stability testing was also performed at 300°C, showing very little drift at over 100 hours for the individual MOSFETs and the common source amplifier.

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Transient voltage suppressors (TVS) fabricated in silicon carbide (SiC) and subjected to extensive surge testing is presented. The SiC TVS devices can work at high temperatures, have high current density capability, are smaller and have lower capacitance than comparable Si devices. They are also rugged and reliable, capable of withstanding multiple back-to-back lightning hits. These devices are expected to provide enhanced surge protection for composite aircrafts and enable high temperature power electronics circuits.