Method of manufacturing a magnetoresistive sensor
AssigneeInternational Business Machines Corporation
InventorsHardayal S. Gill, Tsann Lin, Ching H. Tsang, Albert J. Wallash
Life of this patent
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Abstract
In a magnetoresistive (MR) read sensor in which the MR layer is transversely biased by a soft magnetic layer separated from the MR layer by a nonmagnetic spacer layer an antiferromagnetic stabilization layer of NiO provides a stabilizing exchange-coupled magnetic field to the transverse bias layer insuring that the transverse bias layer is fully saturated in a preferred direction during sensor operation.
Claims15
A method or fabricating a magnetoresistive sensor of the type having a transverse bias layer of ferromagnetic material separated from a magnetoresistive layer by a nonmagnetic spacer layer, said transverse bias layer for providing a transverse bias magnetic field in said magnetoresistive layer, and a longitudinal bias layer of an antiferromagnetic material formed in direct contact with said magnetoresistive layer for providing an exchange-coupled longitudinal bias field in said magnetoresistive layer, wherein a stabilization layer of an antiferromagnetic material is in direct contact with said transverse bias layer for inducing an exchange-coupled magnetic field in said transverse bias layer, said method comprising the steps of:
- depositing a stabilization layer of a first antiferromagnetic material on a substrate;
- depositing a transverse bias layer of a ferromagnetic material over and in contact with said stabilization layer;
- depositing a spacer layer of a nonmagnetic material over said transverse bias layer;
- depositing a layer of magnetoresistive material over said spacer layer, said magnetoresistive layer separated from said transverse bias layer by said spacer layer;
- depositing a longitudinal bias layer of a second antiferromagnetic material over said magnetoresistive layer and in direct contact with said magnetoresistive layer, said first and second antiferromagnetic materials having different Neel temperatures;
- annealing said magnetoresistive sensor at a temperature approximately equal to the higher of the Neel temperatures of said first and second antiferromagnetic materials in the presence of a magnetic field having a desired direction for setting the direction of the exchange-coupled magnetic field induced by the first or second antiferromagnetic material associated with the higher of the two Neel temperatures;
- and
- annealing said magnetoresistive sensor at a temperature approximately equal to the lower of the Neel temperatures of said first and second antiferromagnetic materials in the presence of a magnetic field having a desired direction for setting the direction of the exchange-coupled magnetic field induced by the first or second antiferromagnetic material associated with the lower of the two Neel temperatures.
A method for fabricating a magnetoresistive sensor of the type having a transverse bias layer of ferromagnetic material separated from magnetoresistive layer by a nonmagnetic spacer layer formed in a central region of said magnetoresistive sensor, said transverse bias layer for providing a transverse bias magnetic field in said magnetoresistive layer, and a longitudinal bias layer of a high coercivity material formed in end regions of said magnetoresistive sensor, said end regions separated by said central region, said longitudinal bias layer for providing a longitudinal bias field in said magnetoresistive layer, wherein a stabilization layer of an antiferromagnetic material is in direct contact with said transverse bias layer for inducing an exchange-coupled magnetic field in said transverse bias layer, said method comprising the steps of:
- depositing a stabilization layer of an antiferromagnetic material on a substrate;
- depositing a transverse bias layer of a ferromagnetic material over and in contact with said stabilization layer;
- depositing a spacer layer of a nonmagnetic material over said transverse bias layer;
- depositing a layer of magnetoresistive material over said spacer layer, said magnetoresistive layer separated from said transverse bias layer by said spacer layer;
- patterning said transverse bias layer, said spacer layer and said magnetoresistive layer to extend over only said central region;
- depositing a longitudinal bias layer of a high coercivity material in said end regions of said magnetoresistive sensor for providing a longitudinal bias field in said magnetoresistive layer;
- saturating said longitudinal bias layer with an externally applied magnetic field having a desired direction with respect to the longitudinal axis of said magnetoresistive layer for setting the magnetic field direction of said longitudinal bias layer;
- and
- annealing said magnetoresistive sensor at a temperature approximately equal to the Neel temperature of antiferromagnetic material in the presence of a magnetic field having a desired direction for setting the direction of the exchange-coupled magnetic field induced in the transverse bias layer by said stabilization layer.
Dependencies are inferred from the claim text.