US 12,287,381 B2
Magnetoresistive sensor element for sensing a two-dimensional magnetic field with low high-field error
Clarisse Ducruet, Chambéry (FR); Léa Cuchet, Moirans (FR); and Jeffrey Childress, San Jose, CA (US)
Assigned to Allegro MicroSystems, LLC, Manchester, NH (US)
Appl. No. 17/905,352
Filed by Allegro MicroSystems, LLC, Manchester, NH (US)
PCT Filed Mar. 2, 2021, PCT No. PCT/IB2021/051724
§ 371(c)(1), (2) Date Aug. 31, 2022,
PCT Pub. No. WO2021/181203, PCT Pub. Date Sep. 16, 2021.
Claims priority of application No. 20315038 (EP), filed on Mar. 11, 2020.
Prior Publication US 2023/0127582 A1, Apr. 27, 2023
Int. Cl. H10N 50/10 (2023.01); G01R 33/09 (2006.01); H01F 10/32 (2006.01); H10N 50/85 (2023.01)
CPC G01R 33/098 (2013.01) [G01R 33/093 (2013.01); H01F 10/3272 (2013.01); H10N 50/10 (2023.02); H10N 50/85 (2023.02)] 3 Claims
OG exemplary drawing
 
1. A magnetoresistive element for a two-dimensional magnetic field sensor, comprising:
a ferromagnetic reference layer having a fixed reference magnetization, a ferromagnetic sense layer having a sense magnetization that can be freely oriented relative to the reference magnetization in the presence of an external magnetic field, and a tunnel barrier layer between the reference and sense ferromagnetic layers;
the reference layer comprising a reference coupling layer between a reference pinned layer and a reference coupled layer;
the reference coupled layer comprises a first coupled sublayer in contact with the reference coupling layer, a second coupled sublayer in contact with the first coupled sublayer, a third coupled sublayer and an insert layer between the second and third coupled sublayers, the insert layer providing a ferromagnetic exchange coupling between the second and third coupled sublayers; and
the insert layer has a thickness of 0.2 nm;
wherein the reference pinned layer comprises a CoFe alloy and has a thickness of 2 nm, the tunnel barrier layer comprises Mg;
wherein the insert layer comprises Ta, the first coupled sublayer is made of a CoFe alloy, 0.5 nm in thickness, the second coupled sublayer is made of a CoFeB alloy and has a thickness of 0.75 nm, and the third coupled sublayer is made of a CoFeB alloy and has a thickness between 0.45 nm and 0.95 nm;
wherein the magnetoresistive element is thermally treated at 310° C. during 90 min under an applied magnetic field of about 1T.