US 12,092,706 B2
Magnetic field sensor for sensing a two-dimensional external magnetic field having a low anisotropy field
Léa Cuchet, Moirans (FR); Clarisse Ducruet, Chambéry (FR); and Jeffrey Childress, San Jose, CA (US)
Assigned to Allegro MicroSystems, LLC, Manchester, NH (US)
Appl. No. 17/597,195
Filed by Allegro MicroSystems, LLC, Manchester, NH (US)
PCT Filed Jun. 26, 2020, PCT No. PCT/IB2020/056073
§ 371(c)(1), (2) Date Dec. 29, 2021,
PCT Pub. No. WO2021/001738, PCT Pub. Date Jan. 7, 2021.
Claims priority of application No. 19315051 (EP), filed on Jul. 2, 2019.
Prior Publication US 2022/0308133 A1, Sep. 29, 2022
Int. Cl. G01R 33/09 (2006.01); G01R 15/20 (2006.01)
CPC G01R 33/098 (2013.01) [G01R 15/205 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A method for manufacturing a magnetic field sensor comprising a magnetic tunnel junction comprising a reference layer having a fixed reference magnetization oriented in the plane of the reference layer, a sense ferromagnetic layer having a sense magnetization orientable in the plane of the sense ferromagnetic layer, and a tunnel barrier layer between the sense ferromagnetic layer and the reference layer, the sense ferromagnetic layer comprising a first sense ferromagnetic layer in contact with the tunnel barrier layer, a second sense ferromagnetic layer, and a first non-magnetic layer between said first and second sense ferromagnetic layers, wherein said second sense ferromagnetic layer comprises a plurality of multilayer elements, each multilayer element comprising a second non-magnetic layer between two second ferromagnetic sense layers, wherein said second sense ferromagnetic layer has a thickness equal to or less than 20 nm, the method comprising the steps of:
depositing the reference layer, the tunnel barrier layer, the first sense ferromagnetic layer, the first non-magnetic layer, and the second sense ferromagnetic layer,
wherein said depositing the second sense ferromagnetic layer comprises depositing the plurality of multilayer elements including, for each multilayer element, sequentially depositing the second non-magnetic layer between two second ferromagnetic sense layers,
wherein the first sense ferromagnetic layer and the second sense ferromagnetic layer are made of a ferromagnetic material that does not comprise a refractory metal, and
wherein each multilayer element is deposited on a substrate with a deposition angle (θ) that differs from the deposition angle of a subsequent multilayer element;
wherein said deposition angle is defined relative to a reference angle on the substrate on which the multilayer element is deposited.