Sub 60nm etchless MRAM devices by ion beam etching fabricated T-shaped bottom electrode

A device comprising:

• a first electrode having a first cross-sectional shape;
• a second electrode disposed directly on the first electrode, the second electrode having a second cross-section shape that is different than the first cross-sectional shape;
• a first magnetic tunneling junction (MTJ) structure disposed directly on the second electrode, wherein no portion of the first MTJ structure is disposed directly on the first electrode;
• a second MTJ structure disposed directly on the first electrode, wherein no portion of the second MTJ structure is disposed directly on the second electrode;
• a dielectric layer extending from the second MTJ structure to the first MTJ structure, the dielectric layer being formed of the same material throughout the dielectric layer,
• wherein a top surface of the first MTJ structure and a top surface of the dielectric layer are coplanar,
• wherein the dielectric layer extends from a top surface of the second MTJ structure to the third electrode, and
• wherein the top surface of the second MTJ structure faces away from the first electrode.

A device comprising:

• a first electrode;
• a T-shaped electrode disposed directly on the first electrode;
• a first magnetic tunneling junction (MTJ) structure disposed directly on the T-shaped electrode and extending to a first height above the first electrode;
• a second MTJ structure disposed directly on the first electrode and extending to a second height above the first electrode that is less than the first height, wherein the first MTJ structure and the second MTJ structure are formed of the same material layers;
• and
• an encapsulation layer extending from the second MTJ structure to the first MTJ structure, the encapsulation layer being formed of the same material throughout the encapsulation layer,
• wherein the encapsulation layer covers a top surface of the second MTJ structure.