AlGaN/GaN magnetic sensors featuring heterojunction 2DEG channel

Abstract Magnetic sensors based on the principle of Hall effect are widely used in various applications for detection and control of displacement, speed, angle, and rotation speed. Nowadays, the conventional Hall sensors are made of the narrow bandgap semiconductors. The typical ones are silicon (Si), indium antimonide (InSb), and gallium arsenide (GaAs). With the rapid increase in the need for high-temperature magnetic detections especially in the space exploration and thermonuclear power stations, they cannot meet the requirement of operation at high temperature due to the limitation of their natural characteristics such as low carrier mobility or small bandgap. In this work, the Hall sensors based on the third-generation semiconductor gallium nitride (GaN) were demonstrated by employing both the simulation and device fabrication schemes. The developed AlGaN/GaN heterojunction Hall sensors benefited from the presence of two-dimensional electron gas (2DEG) are small in size, and have an improved magnetic sensitivity and stability at high temperature. They exhibit a large current-related magnetic sensitivity up to 94.6 V A −1 T −1 and a low temperature coefficient less than 745 ppm K −1 , which is obviously improved compared with those in the currently commercialised semiconductor Hall sensors. Moreover, the Hall sensors developed in this work can be widely used in various harsh environments with high temperature (>573 K) and intense radiation in future.