Effect of Geometry on Sensitivity and Offset of AlGaN/GaN and InAlN/GaN Hall-Effect Sensors

The effect of metal contact lengths on current- and voltage-scaled sensitivities and magnetic field offsets of octagonal AlCaN/GaN and InAIN/GaN Hall-effect sensors were examined in this work. The calculations that take into account the shape of the device show that the devices with point-like contacts have the highest current-scaled sensitivity (68.9 V/A/T), while the devices with contacts of equal length to their non-contact sides have the highest voltage-scaled sensitivity (86.9 mV/V/T). The sensitivities of the two other devices (with "long" and "short" contacts) follow the predicted trends closely. All the devices have offsets less than 20 mu T at low supply current operation (<300 mu A) and most remain below 35 mu T at higher supply current (up to 1.2 mA). The consistent low offsets across the devices imply that the choice of the Hall-effect sensor geometry should mainly depend on the biasing scheme (e.g., current or voltage). Although this work focuses on 2DEG materials, the geometry dependence can be applied to other planar Hall-effect sensors with four-fold symmetry. This work demonstrates that the Hall-effect sensor performance can be improved by adjusting the geometry of the Hall-effect plate specific to its function (e.g., power electronics, navigation, and automotive applications).