Tunnel magnetoresistance read head with narrow shield-to-shield spacing
View Patent ↗A tunnel magnetoresistance (TMR) read sensor having a tabbed AFM layer and an extended pinned layer and methods for making the same are provided. The TMR read sensor has an AFM layer recessed from the air bearing surface, providing a reduced shield-to-shield distance.
1. A method, comprising:
obtaining a substrate comprising a shield layer;
depositing an antiferromagnetic layer over the shield layer
depositing an antiferromagnet exchange biased pinned layer over the antiferromagnetic layer;
forming a photoresist pattern on the antiferromagnet exchange biased pinned layer for a read sensor seed layer deposition;
etching the antiferromagnet exchange biased first pinned layer, the antiferromagnetic layer, and a portion of the shield layer to form a region for the read sensor seed layer deposition, the region located such that the remaining antiferromagnet exchange biased first pinned layer and antiferromagnetic layer are recessed from an air bearing surface plane; and
depositing the read sensor seed layer in the region.
2. The method of claim 1 , further comprising:
etching the substrate for surface planarization after depositing the read sensor seed layer in the region;
depositing a second pinned layer over the remaining antiferromagnet exchange biased first pinned layer and the read sensor seed layer intersecting the air bearing surface plane;
depositing a barrier layer over the second pinned layer and intersecting the air bearing surface plane;
depositing a free layer over the barrier layer and intersecting the air bearing surface plane; and
depositing a capping layer over the free layer and intersecting the air bearing surface plane.
3. The method of claim 1 , wherein the steps of etching the antiferromagnet exchange biased first pinned layer to form a region for the read sensor seed layer deposition and depositing the read sensor seed layer are performed in situ.
4. The method of claim 1 , wherein the steps of etching the antiferromagnet exchange biased first pinned layer, the antiferromagnetic layer, and a portion of the shield layer and depositing the read sensor seed layer are performed ex situ.
5. The method of claim 1 , wherein the step of depositing the antiferromagnet exchange biased first pinned layer comprises:
depositing a first soft ferromagnetic layer over the antiferromagnetic layer;
depositing a non-magnetic layer over the first soft ferromagnetic layer; and
depositing a second soft ferromagnetic layer over the non-magnetic layer; and
the non-magnetic layer having a thickness approximately equal to a first or a second oscillatory peak of the exchange coupling between the first soft ferromagnetic layer and the second soft ferromagnetic layer; and
the non-magnetic layer comprising Ru, Cr, Ag, or Au.
6. The method of claim 1 , further comprising magnetically annealing the assembly formed after the step of depositing the capping layer.