Magnetic field sensors based on silicon carbide for very high temperatures
We explore the feasibility of magnetic field sensors based on silicon carbide for very high temperatures exceeding 400° C. Such high temperatures may be encountered, e.g., in deep geo-thermal wells and future planetary explanation missions. Due to the wide-band gap nature of SiC, the carrier density is stable over a very wide temperature range, enabling the realization of high temperature electronics and sensors. Although stack-based magnetoresistive sensors exhibit high resolution, theoretically up to very high temperatures, their operation temperature is limited by the onset of interlayer diffusion between the different sensor layers, thus limiting the operation to temperatures below 300°C. On the other hand at very high temperatures, Hall-based semiconductor magnetic sensors, which rely on the Lorentz deflection of charge carriers in a semiconducting active region, become a practical candidate. The goal of our study is to investigate different sensor designs and draw a conclusion on the most promising ones with respect to magnetic sensitivity and resulting magnetic resolution at the desired very high temperature operation range.