Designs of Slope Magnetic Flux Guides for 3-Axis Magnetic Sensor

Generally, giant magnetoresistive (GMR) sensors are only sensitive to the magnetic field in the plane of the substrate due to fabrication restraints. This paper designs and models slope magnetic flux guides that are deposited on the slope surface of a silicon substrate. Finite element method (FEM) simulations are used to optimize the flux guide designs. The flux guides can be deposited with good symmetry and are able to convert the out-of-plane magnetic flux to the GMR sensor plane. Meanwhile, a Wheatstone bridge is configured to deduce a differential voltage only relative to the z-component of the magnetic field. Additionally, the magnetic field in the active region of the GMR sensor would be intensified. With these flux guides, the magnetic field perpendicular to the chip surface can be detected with the GMR sensors in-plane. Also, the sensitivity of the sensor can be improved due to the amplification ability of the flux guides. An integrated 3-axis magnetic sensor with better angular position can be realized with the slope flux guides.