Residual Offset in Silicon Hall-Effect Sensor: Analytical Formula, Stress Effects, and Implications for Octagonal Hall Plate Geometry

Abstract

The Hall-effect magnetic sensors suffer from large offset that is described by the resistance mismatch in the Wheatstone bridge-like equivalent electrical circuit model of the Hall plate. After a first order cancellation of the raw offset using spinning current technique, a residual offset still exists, significantly limiting the accuracy of the Hall sensor in the detection of low magnetic field. In this paper we analyzed the residual offset in silicon Hall sensor using a nonlinear lumped resistor network model to derive a closed form expression. We further analyzed the residual offset in silicon Hall sensor under the influence of stress. Using these results, we show that eight-terminal, octagonal-shaped silicon Hall sensors employing eight-phase spinning current technique provide greater immunity to stress effects on residual offset due to a second order cancellation compared to the conventional four-phase spinning. The measurement results suggest superior offset performance of eight-terminal silicon Hall sensor.