Investigation of AlGaN∕AlN∕GaN heterostructures for magnetic sensor application from liquid helium temperature to 300°C

We report a comparative investigation of the magnetic response of long channel AlGaN∕AlN∕GaN heterostructures (Hall-field effect transistor devices) grown on three different semi-insulating templates on silicon and sapphire. From Hall effect measurements conducted up to 573K (300°C), we find that some of these specific devices can be used as magnetic sensors in a large temperature range (∼600°C) with a magnetic sensitivity close to 60V∕AT and a small thermal drift. On the best sample, between liquid helium temperature and 300°C, the average value of the thermal drift is only −7ppm∕°C.