Spin-orbit torque (SOT) magnetoresistive random-access memory (MRAM) with low resistivity spin hall effect (SHE) write line
Embodiments of the invention include a method for fabricating a magnetoresistive random-access memory (MRAM) structure and the resulting structure. A first type of metal is formed on an interlayer dielectric layer with a plurality of embedded contacts, where the first type of metal exhibits spin Hall effect (SHE) properties. At least one spin-orbit torque (SOT) MRAM cell is formed on the first type of metal. One or more recesses surrounding the at least one SOT-MRAM cell are created by recessing exposed portions of the first type of metal. A second type of metal is formed in the one or more recesses, where the second type of metal has lower resistivity than the first type of metal.
1. A magnetoresistive random-access memory (MRAM) structure comprising:
a write line comprising alternating types of metal along a plane, wherein:
a first type of metal, of the alternating types of metal, exhibits spin Hall effect (SHE) properties; and
a second type of metal, of the alternating types of metal, has lower resistivity than the first type of metal; and
a spin-orbit torque (SOT) MRAM cell on top of the write line, perpendicular to the plane, wherein a free layer of the SOT-MRAM cell contacts the first type of metal.
2. The MRAM structure of claim 1 , wherein one SOT-MRAM cell is on top of each separate occurrence of the first type of metal along the alternating types of metal of the write line.
3. The MRAM structure of claim 1 , wherein the SOT-MRAM cell comprises a reference layer and the free layer separated by a tunneling barrier.
4. The MRAM structure of claim 1 , further comprising a plurality of contacts contacting the write line.
5. The MRAM structure of claim 1 , wherein the second type of metal is selected from the group consisting of: ruthenium (Ru), copper (Cu), and cobalt (Co).
6. The MRAM structure of claim 1 , wherein the first type of metal is a heavy metal/alloy where the spin-orbit interaction is strong.
7. The MRAM structure of claim 1 , further comprising a dielectric layer on sidewalls of the SOT-MRAM cell.
8. The MRAM structure of claim 1 , further comprising a contact contacting the top surface of the SOT-MRAM cell.
9. The MRAM structure of claim 1 , wherein the width of the write line along a plane is smaller than the width of the SOT-MRAM cell along the plane.
10. The MRAM structure of claim 1 , wherein the width of the write line along a plane is greater than the width of the SOT-MRAM cell along the plane.