Temperature sensor based on 4H siliconcarbide with measurement range up to 400°C

Abstract

Wide band gap semiconductor has attracted significant industrial interest over the past decade with its superior properties: such as high critical electrical field, high thermal conductivity andwide band gap. Meanwhile many industries operating in harsh environments have long had demands for sensing solutions that function at high temperature. Current commercially available silicon-based temperature sensing IC has measure range limited to 155°C . This research work aims to develop a temperature sensor based on 4H silicon carbide with pronounced higher measurement range but comparable linearity. Furthermore, this work introduces silicon carbide based bipolar junction transistor (BJT) technology in the Else Kooi Lab (EKL).
Ratio-metric measurement technique from CMOS technology is adapted to eliminate PN diode and BJT’s non-linearity as a temperature sensor; and devices are implemented experimentally on epitaxial 4H-silicon carbide wafers in the EKL.
The characterization data shows that diode version sensor operates to 400 °C with a R2 value of 0.9963, the sensitivity under 1 mA constant current source is 4.8mV/°C . The BJT version operates to 200 °C with a R2 of 0.9965. In the future the sensor’s integration with pressure, gas, and other types of sensing solutions can provide a comprehensive sensing package. Such a package can be used to predict life time of critical components in harsh environment installations; and hence reduce the maintenance cost. Examples
of application scenarios include oil&gas exploration, industrial furnaces, geothermal extraction,and so on.