High-performance Hall sensors based on III–V heterostructures

Abstract

Abstract Hall sensors with a high sensitivity, a low thermal drift and a low offset voltage based on AlGaAs/InGaAs/GaAs heterostructures have been developed. The physical phenomena responsible for the thermal drift of the Hall sensitivity are reviewed and investigated using a set of test devices with well-controlled structure parameters. These results have been used to optimize the design of sensors with a Hall factor in the 1000 V/A/T range in order to reduce the temperature sensitivity of the channel electron density down to a few 100 ppm/°C. The dependence of the Hall factor and of its thermal drift on the bias current has been investigated. We show that the bias-current level can be tuned to achieve a very low thermal drift together with a high absolute sensitivity in the range 0.4–0.5 V/T.