Sensitivity of 2DEG-based Hall-effect sensors at hightemperatures

The magnetic sensitivity of Hall-effect sensors made of InAlN/GaN and AlGaN/GaNheterostructures was measured between room temperature and 576 °C. Both devices showeddecreasing voltage-scaled magnetic sensitivity at high temperatures, declining from 53mV/V/T to 8.3 mV/V/T for the InAlN/GaN sample and from 89 mV/V/T to 8.5 mV/V/T for theAlGaN/GaN sample, corresponding to the decreasing electron mobility due to scatteringeffects at elevated temperatures. Alternatively, current-scaled sensitivities remainedstable over the temperature range, only varying by 13.1% from the mean of 26.3 V/A/T and10.5% 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 the2-dimensional electron gas (2DEG). Both devices showed consistency in their voltage- andcurrent-scaled sensitivity over multiple temperature cycles as well as nearly fullrecovery when returned to room temperature after thermal cycling. Additionally, anAlGaN/GaN sample held at 576 °C for 12 h also showed nearly full recovery at roomtemperature, further suggesting that GaN-based Hall-effect sensors are a good candidatefor use in high temperature applications.