Nxp B.v.

Hartmut Matz

Jörg Kock

Mark Isler

Klaus Reimann

Stephan Marauska

Dennis Helmboldt

A magnetic field sensor includes a magnetic sense element and a shield structure formed on a substrate. The shield structure fully encircles the magnetic sense element for suppressing stray magnetic fields along a first axis and a second axis, both of which are parallel to a surface of the substrate and perpendicular to one another. A magnetic field is oriented along a third axis perpendicular to the surface of the substrate, and the magnetic sense element is configured to sense a magnetic field along the first axis. A magnetic field deflection element, formed on the substrate proximate the magnetic sense element, redirects the magnetic field from the third axis into the first axis to be sensed as a measurement magnetic field by the magnetic sense element. At least two magnetic field sensors, each fully encircled by a shield structure, form a gradient unit for determining a magnetic field gradient.

Stray magnetic field robust magnetic field sensor and system

A method includes performing an ion beam etching process on a tunnel magnetoresistance (TMR) stack to remove material portions of a first magnetic layer and a tunnel barrier layer of the TMR stack. The ion beam etching process stops at a top surface of a second magnetic layer of the TMR stack. A protective layer is deposited over the TMR stack. Another etch process is performed to remove the protective layer such that a portion of the second magnetic layer is exposed from the protective layer and a spacer is formed from a remaining portion of the protective layer. The spacer surrounds sidewalls of the first magnetic layer and the tunnel barrier layer. The portion of the second magnetic layer exposed from the protective layer is removed so that a TMR sensor element remains, where the TMR sensor element includes a bottom magnet, a top magnet, and a tunnel junction.

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Hamburg, Germany

Hartmut Matz