Patent ID: 8647891

Claim:
A method for fabricating a magnetoresistive thin-film magnetic field sensor, comprising: providing a substrate; forming an insulating layer over the substrate; forming a sensor layer stack over the insulating layer, the sensor layer stack comprising: a pinning layer formed over the insulating layer; a pinned layer comprising: an amorphous ferromagnetic layer having a thickness in the range of 2 to 15 Angstroms formed over the pinning layer; and a crystalline ferromagnetic layer formed over the amorphous ferromagnetic layer; a nonmagnetic coupling layer formed over the pinned layer; a ferromagnetic fixed layer formed over the nonmagnetic coupling layer; a dielectric tunnel barrier formed over the ferromagnetic fixed layer; and a ferromagnetic sense layer formed over the dielectric tunnel barrier layer; selectively etching the sensor layer stack to form a first electrode stack and a second electrode stack, where the first electrode stack has a first shape anisotropy to set a first reference direction, and where the second electrode stack has a second shape anisotropy to set a second reference direction; applying a saturating field substantially parallel to the substrate that is oriented between the first and second reference directions until each reference layer structure of the first and second electrode stacks has a magnetization that is substantially aligned with the saturating field; and removing the saturating field to allow the first shape anisotropy to set the magnetization of the reference layer structure of the first electrode stack, and to allow the second shape anisotropy to set the magnetization of the reference layer structure of the second electrode stack.