Schottky-Diode-Enhanced Ultralow Bias AlGaN/GaN Magnetoresistive Sensor Design

This work presents an AlGaN/GaN-based magnetoresistive sensor design providing an enhanced magnetic sensitivity ( \Delta {R}/\Delta {B} ) at nanowatt-level power consumption. The design embodies a Schottky diode in series with the geometrical magnetoresistance (MR) unit. The overall MR response can be significantly enhanced by the shift of the diode's conductivity, especially when operating in its subthreshold bias region. At a bias current of 50 nA, the design with Ni/TiN diode achieves a \Delta {R}/\Delta {B} value of 46.34~\Omega /mT at room temperature, which is over 100 times greater than that of the single geometrical MR unit ( 0.44~\Omega /mT) at the same bias. Furthermore, the diode-assisted design consumes only 26.96 nW, making it significantly more efficient than the MR unit alone, which needs to consume 30.52~\mu W for the same sensitivity.