Magnetoresistive random access memory device having a metal layer doped with a magnetic material
A magnetoresistive random access memory device includes a pinned layer; a tunnel barrier layer on the pinned layer; a free layer structure on the tunnel barrier layer, the free layer structure including a plurality of magnetic layers and a plurality of metal insertion layers between the magnetic layers; and an upper oxide layer on the free layer structure, wherein each of the metal insertion layers includes a non-magnetic metal material doped with a magnetic material, and the metal insertion layers are spaced apart from each other.
1. A magnetoresistive random access memory device, comprising:
a pinned layer;
a tunnel barrier layer on the pinned layer;
a free layer structure on the tunnel barrier layer, the free layer structure including a plurality of magnetic layers and a plurality of metal insertion layers between adjacent ones of the plurality of magnetic layers; and
an upper oxide layer on the free layer structure,
wherein:
each metal insertion layer of the plurality of metal insertion layers includes a non-magnetic metal material doped with a magnetic material,
the magnetic material doped into each metal insertion layer of the plurality of metal insertion layers has a structure including particles extending in a vertical direction between adjacent magnetic layers of the plurality of magnetic layers, and
each metal insertion layer is spaced apart from each other metal insertion layer of the plurality of metal insertion layers.
2. The magnetoresistive random access memory device as claimed in claim 1 , wherein each metal insertion layer of the plurality of metal insertion layers has a thickness of 2 Å to 10 Å.
3. The magnetoresistive random access memory device as claimed in claim 1 , wherein the magnetic material included in each metal insertion layer of the plurality of metal insertion layers has a concentration of 5 at % to 40 at %.
4. The magnetoresistive random access memory device as claimed in claim 3 , wherein the magnetic material included in each metal insertion layer of the plurality of metal insertion layers has a concentration of 20 at % to 40 at %.
5. The magnetoresistive random access memory device as claimed in claim 1 , wherein the magnetic material doped into each metal insertion layer of the plurality of metal insertion layers is partially connected in a vertical direction.
6. The magnetoresistive random access memory device as claimed in claim 1 , wherein:
the magnetic material doped into each metal insertion layer of the plurality of metal insertion layers has a structure connected in a vertical direction, and
the magnetic material has a magnetic bridge pattern vertically connected to adjacent ones of the plurality of magnetic layers.
7. The magnetoresistive random access memory device as claimed in claim 1 , wherein each metal insertion layer of the plurality of metal insertion layers is continuously on one magnetic layer of the plurality of magnetic layers such that adjacent magnetic layers of the plurality of magnetic layers are separated by one metal insertion layer of the plurality of metal insertion layers.
8. The magnetoresistive random access memory device as claimed in claim 1 , wherein a sum of thicknesses of the plurality of magnetic layers included in the free layer structure is greater than a sum of thicknesses of the plurality of metal insertion layers included in the free layer structure.
9. The magnetoresistive random access memory device as claimed in claim 1 , wherein:
the non-magnetic metal material included in each metal insertion layer of the plurality of metal insertion layers includes molybdenum, tungsten, tantalum, ruthenium, zirconium, niobium, yttrium, scandium, vanadium, chromium, tellurium, or hafnium, and
the magnetic material doped into the non-magnetic metal material includes iron, cobalt, gadolinium or nickel.
10. A magnetoresistive random access memory device, comprising:
a pinned layer;
a tunnel barrier layer on the pinned layer;
a free layer structure on the tunnel barrier layer; and
an upper oxide layer on the free layer structure;
wherein the free layer structure includes:
a first magnetic layer,
a first metal insertion layer on the first magnetic layer, the first metal insertion layer including a first non-magnetic metal material doped with a first magnetic material,
a second magnetic layer on the first metal insertion layer,
a second metal insertion layer on the second magnetic layer, the second metal insertion layer including a second non-magnetic metal material doped with a second magnetic material, and
a third magnetic layer on the second metal insertion layer; and
wherein the first magnetic material doped into the first metal insertion layer has a structure including particles extending in a vertical direction between the first magnetic layer and the second magnetic layer, and
wherein the second magnetic material doped into the second metal insertion layer has a structure including particles extending in a vertical direction between the second magnetic layer and the third magnetic layer.
11. The magnetoresistive random access memory device as claimed in claim 10 , wherein:
the first magnetic material doped into the first metal insertion layer is vertically connected to the first magnetic layer and the second magnetic layer, and
the second magnetic material doped into the second metal insertion layer is vertically connected to the second magnetic layer and the third magnetic layer.
12. The magnetoresistive random access memory device as claimed in claim 10 , wherein each of the first metal insertion layer and the second metal insertion layer has a thickness of 2 Å to 10 Å.
13. The magnetoresistive random access memory device as claimed in claim 10 , wherein:
the first magnetic material included in the first metal insertion layer has a concentration of 5 at % to 40 at %, and
the second magnetic material included in the second metal insertion layer has a concentration of 5 at % to 40 at %.
14. The magnetoresistive random access memory device as claimed in claim 10 , wherein:
the first non-magnetic metal material included in the first metal insertion layer and the second non-magnetic metal material included in the second metal insertion layer each include molybdenum, tungsten, tantalum, ruthenium, zirconium, niobium, yttrium, scandium, vanadium, chromium, tellurium, or hafnium, and
the first magnetic material doped into the first non-magnetic metal material and the second magnetic material doped into the second non-magnetic metal material each include iron, cobalt, gadolinium or nickel.
15. The magnetoresistive random access memory device as claimed in claim 10 , wherein the upper oxide layer includes magnesium oxide, magnesium aluminum oxide, hafnium oxide, zirconium oxide, aluminum oxide, tantalum oxide, or iridium oxide.
16. The magnetoresistive random access memory device as claimed in claim 10 , wherein the upper oxide layer has a thickness of 2 Å to 15 Å.
17. A magnetoresistive random access memory device, comprising:
a pinned layer;
a tunnel barrier layer on the pinned layer;
a free layer structure on the tunnel barrier layer; and
an upper oxide layer on the free layer structure,
wherein the free layer structure includes:
a first magnetic layer having perpendicular magnetic anisotropy and including a ferromagnetic material,
a first metal insertion layer on the first magnetic layer, the first metal insertion layer including a first non-magnetic metal material doped with a first magnetic material,
a second magnetic layer on the first metal insertion layer, the second magnetic layer having perpendicular magnetic anisotropy and including a ferromagnetic material,
a second metal insertion layer on the second magnetic layer, the second metal insertion layer including a second non-magnetic metal material doped with a second magnetic material, and
a third magnetic layer on the second metal insertion layer, the third magnetic layer having perpendicular magnetic anisotropy and including a ferromagnetic material; and
wherein the first magnetic material doped into the first metal insertion layer has a structure including particles extending in a vertical direction between the first magnetic layer and the second magnetic layer, and
wherein the second magnetic material doped into the second metal insertion layer has a structure including particles extending in a vertical direction between the second magnetic layer and the third magnetic layer.
18. The magnetoresistive random access memory device as claimed in claim 17 , wherein:
the first magnetic material doped into the first metal insertion layer is partially connected in a vertical direction, and
the second magnetic material doped into the second metal insertion layer is partially connected in a vertical direction.
19. The magnetoresistive random access memory device as claimed in claim 17 , wherein:
the first magnetic material doped into the first metal insertion layer has a vertically connected structure,
the second magnetic material doped into the second metal insertion layer has a vertically connected structure
the first magnetic material doped into the first metal insertion layer serves as a first magnetic bridge pattern connecting the first magnetic layer and the second magnetic layer in a vertical direction, and
the second magnetic material doped into the second metal insertion layer serves as a second magnetic bridge pattern connecting the second magnetic layer and the third magnetic layer in the vertical direction.
20. The magnetoresistive random access memory device as claimed in claim 17 , wherein the upper oxide layer has a thickness of 2 Å to 15 Å.