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

TL;DR

This study investigates how the geometry of AlGaN/GaN and InAlN/GaN Hall-effect sensors influences their sensitivity and offset, showing that contact shape and device biasing significantly affect performance.

Contribution

It provides a detailed analysis of how contact length and device shape impact sensitivity and offset, offering design guidelines for optimizing GaN Hall-effect sensors.

Findings

Point-like contacts yield highest current-scaled sensitivity.

Equal-length contacts optimize voltage-scaled sensitivity.

All devices maintain low offset (<20 μT) at low currents.

Abstract

The current- and voltage-scaled sensitivities and signal-to-noise ratios (SNR) (with respect to thermal noise) of various octagonal AlGaN/GaN and InAlN/GaN Hall-effect sensors were examined in this work. The effect of metal contact lengths on sensitivity and sensor offset was evaluated. Calculations that take into account the shape of the device show that devices with point-like contacts have the highest current-scaled sensitivity (68.9 V/A/T), while 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 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 Hall-effect sensor geometry should mainly depend on whether the device is current-biased or voltage-biased and the frequency at which it will operate. This work demonstrates that GaN 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, automotive applications).