Hall effect devices are solid state electron devices that operate in response to a magnetic field based upon the Hall effect principle, a phenomenon by which a voltage differential is generated across an electrically conducting body in the presence of a magnetic field. Conventional Hall effect devices typically comprise a planar structure, known as a Hall plate, which is configured to generate an output signal (e.g., either voltage or current) that is proportional to an applied magnetic field. Hall plates may be configured parallel to the surface of a substrate (lateral Hall plates) or perpendicular to the surface of a substrate (vertical Hall plates),
The integration of Hall effect devices (e.g., Hall plates) into semiconductor bodies (e.g., silicon substrate) has become common in many applications. One main problem of Hall effect devices is zero point offset errors, which is a non-zero output signal (e.g., voltage, current) provided by the Hall effect device in the absence of a magnetic field (i.e., magnetic field equal to zero). The offset errors of a Hall effect device may be caused by small asymmetries of the device caused by manufacturing tolerances or mechanical stress or thermo-electric voltages. In order to reduce/remove the offset errors experienced by a Hall effect device, the Hall effect device may be configured to take readings along different orientations of the device. Such methods, known as “current spinning”, send current through a Hall effect device in different directions and combine the output signals in a manner which reduces the offset. For example, a square Hall plate may be rotated by 90° between measurements and then the average of the Hall output signals, over a spinning cycle, may be taken. While current spinning methods may reduce the offset errors, such methods alone fail to completely remove offset errors.
USPTO Backgrounds
USPTO Backgrounds