HIGH-PERFORMANCE HALL SENSORS BASED ON III-V HETEROSTRUCTURES

Hall sensors with a high sensitivity, a low thermal drift and a low of fset voltage based on AlGaAs/InGaAs/GaAs heterostructures have been de veloped. The physical phenomena responsible for the thermal drift of t he 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/degrees-C. The depende nce of the Hall factor and of its thermal drift on the bias current ha s been investigated. We show that the bias-current level can be tuned to achieve a very low thermal drift together with a high absolute sens itivity in the range 0.4-0.5 V/T.