Method of manufacturing a magnetoresistive stack/ structure using plurality of encapsulation layers

A method of manufacturing a magnetoresistive stack/structure from:

• (i) a first magnetic region including one or more layers of magnetic material, (ii) a dielectric layer disposed over the first magnetic region, (iii) a second magnetic region including one or more layers of magnetic material, wherein the second magnetic region is disposed over the dielectric layer, the method comprising:
• (a) etching through the second magnetic region to (i) partially form the magnetoresistive stack/structure and provide sidewalls of the second magnetic region and (ii) expose a surface of the dielectric layer in a field region adjacent to the partially formed magnetoresistive stack/structure;
• (b) depositing a first encapsulation layer on or over the sidewalls of the second magnetic region and on the exposed surface of the dielectric layer, wherein the first encapsulation layer is a first material;
• (c) depositing a second encapsulation layer on the first encapsulation layer disposed (i) on or over the sidewalls of the second magnetic region and (ii) on the exposed surface of the dielectric layer, wherein the second encapsulation layer is a second material;
• (d) after step (c), etching the exposed surface of the dielectric layer together with the first encapsulation layer and the second encapsulation layer disposed on or over the exposed surface of the dielectric layer to form a tunnel barrier, wherein, after the etching in step (d), a portion of the first encapsulation layer and a portion of the second encapsulation layer remain on or over the sidewalls of the second magnetic region;
• and
• (e) after etching through the exposed surface of dielectric layer in step (d), etching the first magnetic region to provide sidewalls thereof.