Silicon carbide integrated circuits for extreme environments

Abstract

Analog and digital integrated circuits capable of operating reliably at 300 °C for 2000 hours were designed and fabricated in silicon carbide. These circuits are critical for the development of tools and instrumentation for geothermal exploration. Lateral MOSFETs and resistors were built on Si-face, 4°-off, N+ 4H-SiC substrates. Compact models of these devices were then generated and used to design the circuits, including operational amplifiers, ring oscillators, counters, shift registers and logic gates. The circuits were then fabricated and packaged using specially developed high temperature packaging processes. The integrated circuits were designed to interface with sensors and transducers to produce analog signals that can be digitized and transmitted via a telemetry system capable of sustained operation at 300 °C.