HIGH-SENSITIVITY HALL SENSORS WITH LOW THERMAL DRIFT USING ALGAAS/INGAAS/GAAS HETEROSTRUCTURES

We have investigated the interest of AlGaAs/InGaAs/GaAs heterostructures for the realization of Hall effect magnetic sensors with a high sensitivity and a low thermal drift. The physical phenomena responsible for the thermal drift of the Hall sensitivity were reviewed. A set of test devices with well-controlled structure parameters were designed in order to investigate and minimize these phenomena. Experimental data were compared with a physical model of the structure including a self-consistent description of the quantum well. These results were used to optimize the structure design. Hall sensors with much higher performances than conventional GaAs devices were fabricated. A sensitivity of 900 V/A/T with a temperature coefficient of - 160 ppm/degrees-C was obtained.