Domain wall assisted spin torque transfer magnetresistive random access memory structure

A method comprising:

• forming an anti-ferromagnetic layer on a substrate;
• forming a ferromagnetic layer on the anti-ferromagnetic layer, wherein
• the ferromagnetic layer includes a first, second and third portions;
• and
• the second portion is located between the first and third portions;
• performing a first ion irradiation to only one portion of the ferromagnetic layer;
• and
• performing a second ion irradiation to only another portion of the ferromagnetic layer.

A semiconductor memory device, comprising:

• an anti-ferromagnetic layer formed over a semiconductor substrate and disposed within a first region of the semiconductor substrate;
• a pinned ferromagnetic layer adjacent the anti-ferromagnetic layer, pinned by the anti-ferromagnetic layer, and disposed within the first region;
• a free ferromagnetic layer approximate the pinned ferromagnetic layer and disposed within the first region;
• a dielectric barrier layer interposed between the pinned ferromagnetic layer and the free ferromagnetic layer for tunneling effect;
• and
• an extended ferromagnetic layer extended from the free ferromagnetic layer, pinned by an additional anti-ferromagnetic feature, and disposed within a second region of the semiconductor substrate, the second region contacting the first region.