High Temperature Smart Sensor for Downhole Logging and Monitoring

High-temperature smart sensors are desired for use in various harsh environment applications. Placing the sensing circuit close to the actual sensor would substantially reduce noise and interference problems and improve system reliability. If the circuits can operate at high temperature, this will reduce total system cost by removing the need for complicated cooling systems and will allow applications where cooling is not possible or practical. The objective of this project is to develop a high temperature smart sensor for geothermal energy applications capable of operation up to 500oC, based on 4H-SiC lateral JFET technology. The system can measure temperature and pressure, and consists of a temperature sensing circuit, a pressure sensing circuit, a voltage reference circuit and a voltage-to-frequency converter circuit, monolithically integrated on one chip. We successfully completed all the tasks on device, circuit and photomask design, and fabrication process development. The design goals were achieved, showing a stable operation of the temperature sensor up to temperatures of 500oC. Proposed to fabricate and package the smart sensor and demonstrate operation at temperatures up to 500oC. Commercial Applications and Other Benefits: Any application that require electrical devices operating in extreme environments, whether high temperature or high radiation will benefit from the proposed program. End use applications range widely from downhole drilling to nuclear instrumentation to motor control applications in hybrid and all electric vehicles.