Patent ID: 8257596
Filing Date: 2012-09-04
Classification: B82Y,G01R,Y10T

Abstract:
1. A method for fabricating a ferromagnetic thin-film based magnetic field sensor comprising two or more reference layer pinning directions, comprising: providing a substrate; forming a first insulating layer over the substrate; depositing a sensor layer stack over the first insulating layer, the sensor layer stack comprising a first ferromagnetic layer formed over the first insulating layer, a nonmagnetic intermediate layer formed on the first ferromagnetic layer, and a second ferromagnetic layer formed on the nonmagnetic intermediate layer, and an antiferromagnetic layer disposed one of between the first ferromagnetic layer and the first insulating layer or on the second ferromagnetic layer, wherein the first or second ferromagnetic layer adjacent the antiferromagnetic layer comprises a reference layer; selectively etching the sensor layer stack to form a first electrode stack and a second electrode stack, the first electrode stack having a first shape anisotropy axis and the second electrode stack having a second shape anisotropy axis; applying an orienting field substantially parallel to the substrate that is oriented between the first and second reference directions to align the magnetization of each reference layer of the first and second electrode in a predetermined direction; removing the orienting field to allow the first shape anisotropy to set the magnetization direction of the reference layer of the first electrode stack, and to allow the second shape anisotropy to set the magnetization direction of the reference layer of the second electrode stack; after removing the orienting field, heating the first and second electrode stacks at or above the pinning temperature of the antiferromagnetic layer in the first and second electrode stacks, and subsequently cooling the first and second electrode stacks, thereby pinning the magnetization of the reference layer in the first electrode stack along a first shape-defined axis, and pinning the magnetization of the reference layer in the second electrode stack along a second shape-defined axis; and providing a first pinned magnetic vector in the first electrode stack in a first desired reference direction and a second pinned magnetic vector in the second electrode stack in a second desired reference direction, by at least one of: