Single-chip double-axis magneto-resistance angle sensor

Abstract

The invention discloses a single-chip double-axis magneto-resistance angle sensor. The sensor comprises a substrate in an X-Y plane and magneto-resistance angle sensors in the push-pull X and Y axes on the substrate, the magneto-resistance angle sensor in the push-pull X axis comprises an X push arm and an X pull arm, the magneto-resistance angle sensor in the push-pull Y axis comprises a Y push arm and a Y pull arm, each of the push arms comprises at least one magneto-resistance angle sensing unit array, magnetic field sensing directions of the magneto-resistance angle sensing unit arrays of the X push arm, the X pull arm, the Y push arm and the Y pull arm are along +X, -X, +Y and -Y directions respectively, each magneto-resistance angle sensing unit includes a TMR / GMR spin valve of the same magnetic multi-layer film structure, a magnetization direction of an anti-ferromagnetic layer is obtained by laser program-control heating magnetic annealing, and a magnetic field attenuation layer can be deposited in the surface of the magneto-resistance angle sensing unit to broaden the working magnetic-field range. The single-chip double-axis magneto-resistance angle sensor has the advantages of compact structure, high precision, small size and capable of realizing the wide working magnetic-field range.

Description

technical field [0001] The invention relates to the field of magnetic sensors, in particular to a single-chip biaxial magnetoresistance angle sensor. Background technique [0002] The dual-axis angle sensor is used to measure the angle information of the external magnetic field in two orthogonal directions such as X and Y directions. It can be used for magnetic wheel speed measurement or encoder angle measurement, and is widely used in the field of magnetic sensor design. [0003] The dual-axis magnetoresistive angle sensor includes two single-axis magnetoresistive angle sensors, X and Y. Each single-axis X or Y magnetoresistive angle sensor usually adopts a push-pull bridge structure to enhance the signal output of the magnetoresistive angle sensor, while the push-pull The pull-type bridge is composed of a push magnetoresistance angle sensing unit and a pull magnetoresistance angle sensing unit, which have opposite magnetic field sensitive directions respectively. [0004]...

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Problems solved by technology

[0004] For TMR or GMR type dual-axis magnetoresistive angle sensors, it is usually used to slice a magnetoresistive sensing unit with a single magnetic field sensitive direction such as the X-axis, and flip it 90, 180 and 270 degrees respectively to obtain the Y-axis derivation. Magnetoresistive sensing unit slices, pull magnetoresistive sensing unit slices, and X-axis push magnetoresistive sensor unit slices and pull magnetoresistive sensor unit slices, therefore, the dual-axis magnetoresistive sensor adopts the method of flipping slices. At least 4 slice slice, its advantage is that the preparation method is simple, only one slice is needed, and it corresponds to a ferromagnetic reference layer structure, and its disadvantage is that it needs to operate four slices to locate in the same plane, which increases the sensor’s failure rate due to operational errors. Potential for loss of measurement accuracy

[0005] The design of the ferromagnetic reference layer with a multilayer film structure can realize the push magnetoresistance of the opposite ferromagnetic reference layer by changing the number of layers of the multilayer film composed of the ferromagnetic layer and the metal spacer layer that are interactively coupled with the antiferromagnetic layer The manufacture of the sensing unit and the pulling magnetoresistive sensing unit; for the orientation of the orthogonal ferromagnetic reference layer, it can be realized by two different antiferromagnetic layers AF1 and AF2 and two times of magnetic field thermal annealing. The disadvantage is that, Due to the need to introduce at least four multilayer film structures and two magnetic field annealings when depositing multilayer films, the complexity of the microfabrication process is increased

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