Magnetic memory devices
A magnetic memory device may include magnetic tunnel junction patterns on a substrate, a conductive line extending between the substrate and the magnetic tunnel junction patterns and in contact with bottom surfaces of the magnetic tunnel junction patterns, and a bottom pattern located between the conductive line and the substrate and in contact with a bottom surface of the conductive line. The material of the conductive line may have a first lattice constant, and the material of the bottom pattern may have a second lattice constant that is less than the first lattice constant of the conductive line. Alternatively or additionally, the bottom pattern includes a metal nitride, and a nitrogen content of the bottom pattern is higher than a metal element content of the metal element.
1. A magnetic memory device comprising:
a magnetic tunnel junction pattern on a substrate;
a conductive line extending between the substrate and the magnetic tunnel junction pattern and in contact with a bottom surface of the magnetic tunnel junction pattern, wherein the conductive line has a first lattice constant; and
a bottom pattern located between the conductive line and the substrate and in contact with a bottom surface of the conductive line, wherein the bottom pattern has a second lattice constant that is less than the first lattice constant of the conductive line.
2. The magnetic memory device of claim 1 , wherein sidewalls of the bottom pattern are aligned with sidewalls of the conductive line relative to a height axis.
3. The magnetic memory device of claim 1 , wherein a thickness of the bottom pattern along a height axis is less than a thickness of the conductive line along the height axis.
4. The magnetic memory device of claim 3 , wherein the thickness of the conductive line along the height axis is at least twice the thickness of the bottom pattern along the height axis.
5. The magnetic memory device of claim 1 , wherein a resistivity of the bottom pattern is greater than a resistivity of the conductive line.
6. The magnetic memory device of claim 1 , wherein the bottom pattern includes a metal nitride.
7. The magnetic memory device of claim 6 , wherein a nitrogen content of the bottom pattern is higher than a metal element content of the bottom pattern.
8. The magnetic memory device of claim 1 , wherein the bottom pattern includes,
a first bottom pattern, and
a second bottom pattern under the first bottom pattern.
9. The magnetic memory device of claim 8 , wherein
the first bottom pattern is a metal nitride layer, and
the second bottom pattern is a metal layer.
10. The magnetic memory device of claim 9 , wherein a thickness of the second bottom pattern along a height axis is less than a thickness of the first bottom pattern along the height axis.
11. The magnetic memory device of claim 8 , wherein the bottom pattern includes a third bottom pattern under the second bottom pattern.
12. The magnetic memory device of claim 11 , wherein a thickness of the third bottom pattern along a height axis is greater than a thickness of the first bottom pattern along the height axis.
13. The magnetic memory device of claim 11 , wherein the third bottom pattern includes a sidewall having a stepped shape.
14. The magnetic memory device of claim 1 , wherein the conductive line is configured to apply spin-orbit torque to the magnetic tunnel junction pattern.
15. The magnetic memory device of claim 1 , wherein
the magnetic tunnel junction pattern includes a set of layers that are sequentially stacked along a height axis, wherein the set of layers includes,
a free layer,
a tunnel barrier pattern, and
a reference layer, and
wherein the free layer is located between the tunnel barrier pattern and the conductive line.
16. A magnetic memory device comprising:
a magnetic tunnel junction pattern on a substrate;
a conductive line extending between the substrate and the magnetic tunnel junction pattern and in contact with a bottom surface of the magnetic tunnel junction pattern; and
a bottom pattern located between the conductive line and the substrate and in contact with a bottom surface of the conductive line,
wherein the bottom pattern includes a metal nitride, and
wherein a nitrogen content of the bottom pattern is higher than a metal element content of the bottom pattern.
17. The magnetic memory device of claim 16 , wherein the bottom pattern provides compressive stress to the conductive line.
18. The magnetic memory device of claim 16 , wherein a ratio of the nitrogen content to the metal element content is substantially between 1.0 and 1.3.
19. The magnetic memory device of claim 16 , wherein a second lattice constant of the bottom pattern is less than a first lattice constant of the conductive line.
20. The magnetic memory device of claim 16 , wherein a grain density of the bottom surface of the conductive line is greater than a grain density of a top surface of the conductive line.