Perpendicular magnetic random-access memory (mram) formation by direct self-assembly method

A magnetic memory device comprising:

• a bottom electrode;
• a magnetic tunneling junction (MTJ) on the bottom electrode, wherein the MTJ comprises a pair of ferromagnetic layers and a dielectric layer between the ferromagnetic layers;
• a top electrode on the MTJ, wherein the ferromagnetic layers, the dielectric layer, and the top electrode collectively make up a columnar structure, and wherein the columnar structure is on the bottom electrode and has a width that is continuous from the bottom electrode to a top surface of the top electrode;
• and
• a sidewall spacer bordering the columnar structure on the bottom electrode, wherein the sidewall spacer has a smooth sidewall that faces away from the columnar structure and that extends continuously from a top corner of the bottom electrode to the columnar structure.

A magnetic memory device comprising:

• a bottom electrode;
• a magnetic tunneling junction (MTJ) overlying the bottom electrode, wherein the MTJ has a width less than about 40 nanometers;
• a top electrode overlying the MTJ, wherein the top electrode and the MTJ have the same planar top layout;
• and
• a sidewall spacer overlying the bottom electrode and bordering the MTJ, wherein the sidewall spacer and the bottom electrode define a common sidewall that is smooth from a bottom corner of the bottom electrode to the top electrode, and wherein the common sidewall has a curved segment at a top of the common sidewall.