Abstract
The authors report experimental investigations on Hall sensors based on AlGaN/GaN heterojunctions grown on silicon 111 (Si 111) substrates. Realisation of two-dimensional electron gas-based Hall sensors on Si substrates can have the advantages of low cost and integrability with complementary metal-oxide semiconductor circuits. Design and fabrication of such Hall sensors and their characterisation over a wide temperature range of 75 to 500 K are reported. The authors experimentally investigate the temperature dependence of the transresistances, sheet resistance and current-related sensitivity (or gain) of such Hall sensors. The current-related sensitivity is shown to be reasonably constant over the complete temperature range and certain inevitable variations in current-related sensitivity can easily be compensated. The temperature dependence of the transresistance can be used for such compensation. The variation of the geometrical correction factor of the Hall sensor with the applied magnetic field strength and the operating temperature is also studied. The authors also demonstrate the possibility of realising Hall sensors with a high geometrical correction factor ( ≈0.97), which is practically insensitive to variations in temperature ( ≃2% from 75 to 500 K) and applied magnetic field, for applications such as in electromechanical devices.
Highlights
Magnetic field sensing is being used widely in many scientific and industrial domains for direct measurement of fields, indirect estimation of physical variables such as position or velocity, detection of material defects etc
While the current‐related sensitivity of Hall sensors based on AlGaN/GaN heterojunctions has been reported extensively [25, 32, 40, 42, 48,49,50,51], studies of such Hall sensors on Si substrates are rather limited [31, 40, 50, 51]
The authors discuss design, fabrication, characterisation and performance evaluation of Hall sensors based on AlGaN/ GaN heterojunctions grown on Si (111) substrates
Summary
Magnetic field sensing is being used widely in many scientific and industrial domains for direct measurement of fields, indirect estimation of physical variables such as position or velocity, detection of material defects etc. An essential requirement of Hall sensing is to establish a thin conducting sheet which is perpendicular to the direction of the magnetic field to be measured. The current related sensitivity of the sensor is studied experimentally over a wide range of temperature from 75 to 500 K under external field strengths up to 2 T. Small Hall sensors are used to measure B at a point In applications such as electric machines where the average B over a certain area is required, Hall elements need to have larger sensing areas. During Hall measurements, the required field strength is adjusted using the magnet power supply It ramps up/down the current in the superconducting magnet at a constant rate of 0.08 A/s until the field set point is reached.
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