Temperature Dependence of Sensitivity of 2DEG-Based Hall-Effect Sensors

TL;DR

This study investigates how the sensitivity of 2DEG-based Hall-effect sensors made from InAlN/GaN and AlGaN/GaN varies with temperature, showing stable current-scaled sensitivity but decreasing voltage-scaled sensitivity at high temperatures, indicating their suitability for high-temperature environments.

Contribution

The paper provides the first detailed analysis of temperature effects on the sensitivity of GaN-based Hall-effect sensors, demonstrating their stability and recovery after thermal cycling.

Findings

Voltage-scaled sensitivity decreases with temperature due to electron mobility reduction.

Current-scaled sensitivity remains stable over temperature range.

Sensors recover nearly fully after thermal cycling and high-temperature exposure.

Abstract

The magnetic sensitivity of Hall-effect sensors made of InAlN/GaN and AlGaN/GaN heterostructures was measured between room temperature and 576{\deg}C. Both devices showed decreasing voltage-scaled magnetic sensitivity at high temperature, declining from 53 to 8.3 mV/V/T for the InAlN/GaN sample and from 89 to 8.5 mV/V/T for the AlGaN/GaN sample, corresponding to the decreasing electron mobility due to scattering effects at elevated temperatures. Alternatively, current-scaled sensitivities remained stable over the temperature range, only varying by 13.1% from the mean of 26.3 V/A/T and 10.5% from the mean of 60.2 V/A/T for the InAlN/GaN and AlGaN/GaN samples respectively. This is due to the minimal temperature dependence of the electron sheet density on the 2-dimensional electron gas (2DEG). Both devices showed consistency in their voltage- and current-scaled sensitivity over multiple temperature cycles as well as nearly full recovery when returned to room temperature after thermal cycling. Additionally, an AlGaN/GaN sample held at 576{\deg}C for 12 hours also showed nearly full recovery at room temperature, further suggesting that GaN-based Hall-effect sensors are a good candidate for use in high temperature applications.