Magnetic tunneling junction device and memory device including the same
Provided are a magnetic tunneling junction device having a relatively high tunneling magnetoresistance (TMR) ratio; and a memory device including the magnetic tunneling junction device. The magnetic tunneling junction device includes: a pinned layer having a first surface and a second surface opposite the first surface; a seed layer disposed in contact with the first surface of the pinned layer; a free layer disposed to face the second surface of the pinned layer; and a tunnel barrier layer disposed between the pinned layer and the free layer, wherein the seed layer includes at least one amorphous material selected from CoFeX and CoFeXTa, and the X includes at least one element selected from niobium (Nb), molybdenum (Mo), tungsten (W), chromium (Cr), zirconium (Zr), and hafnium (Hf). The seed layer may not include boron.
1. A magnetic tunneling junction device comprising:
a pinned layer having a first surface and a second surface opposite the first surface;
a seed layer contacting the first surface of the pinned layer;
a free layer facing the second surface of the pinned layer;
a tunnel barrier layer between the pinned layer and the free layer; and
an anti-crystallized layer between the pinned layer and the tunnel barrier layer,
wherein
the seed layer comprises at least one amorphous material selected from CoFeX and CoFeXTa, and the X is an element selected from niobium (Nb), molybdenum (Mo), tungsten (W), chromium (Cr), and hafnium (Hf), and wherein
the anti-crystallized layer comprises at least one of YCoB, YFeB, or YCoFeB and the Y comprises at least one element selected from tungsten (W), rhenium (Re), molybdenum (Mo), and tantalum (Ta), or
the anti-crystallized layer comprises at least one of ReFe, ReCo, or ReCoFe.
2. The magnetic tunneling junction device of claim 1 , wherein a proportion of the X in the seed layer is 5 at % to 50 at %.
3. The magnetic tunneling junction device of claim 1 , wherein a thickness of the seed layer is 5 Å to 15 Å.
4. The magnetic tunneling junction device of claim 1 , wherein the seed layer is a single layer comprising CoFeXTa.
5. The magnetic tunneling junction device of claim 1 , wherein the seed layer comprises:
a first seed layer facing the first surface of the pinned layer; and
a second seed layer between the pinned layer and the first seed layer to contact the first surface of the pinned layer.
6. The magnetic tunneling junction device of claim 5 , wherein the first seed layer comprises CoFeX and the second seed layer comprises tantalum (Ta).
7. The magnetic tunneling junction device of claim 5 , wherein a thickness of the second seed layer is less than a thickness of the first seed layer.
8. The magnetic tunneling junction device of claim 1 , further comprising:
a polarization enhancing layer between the anti-crystallized layer and the tunnel barrier layer.
9. The magnetic tunneling junction device of claim 8 , wherein the seed layer and the anti-crystallized layer are in an amorphous state at a temperature of 300° C. to 500° C.
10. The magnetic tunneling junction device of claim 1 , wherein
the anti-crystallized layer comprises YFeB,
a proportion of FeB in the anti-crystallized layer is 20 at % to 60 at %, and
a proportion of boron (B) in the FeB is 10 at % to 30 at %.
11. The magnetic tunneling junction device of claim 1 , wherein a thickness of the anti-crystallized layer is 1.5 Å to 10 Å.
12. The magnetic tunneling junction device of claim 8 , wherein the polarization enhancing layer comprises CoFeB.
13. The magnetic tunneling junction device of claim 8 , wherein the polarization enhancing layer comprises:
a first polarization enhancing layer in contact with the anti-crystallized layer; and
a second polarization enhancing layer between the first polarization enhancing layer and the tunnel barrier layer.
14. The magnetic tunneling junction device of claim 13 , wherein each of the first polarization enhancing layer and the second polarization enhancing layer comprises CoFeB, and a proportion of boron (B) in the second polarization enhancing layer is less than a proportion of boron (B) in the first polarization enhancing layer.
15. The magnetic tunneling junction device of claim 14 , wherein
the proportion of boron (B) in the first polarization enhancing layer is 25 at % to 35 at %, and
the proportion of boron (B) in the second polarization enhancing layer is 15 at % to 25 at %.
16. The magnetic tunneling junction device of claim 14 , wherein a thickness of the second polarization enhancing layer is less than a thickness of the first polarization enhancing layer.
17. The magnetic tunneling junction device of claim 16 , wherein the thickness of the first polarization enhancing layer is 5 Å to 7 Å, and the thickness of the second polarization enhancing layer is 1 Å to 3 Å.
18. The magnetic tunneling junction device of claim 17 , wherein
the pinned layer comprises a first ferromagnetic layer in contact with the seed layer, a second ferromagnetic layer in contact with the anti-crystallized layer, and a synthetic antiferromagnet (SAF) coupling layer between the first ferromagnetic layer and the second ferromagnetic layer, and
a magnetization direction of the first ferromagnetic layer and a magnetization direction of the second ferromagnetic layer are opposite to each other.
19. The magnetic tunneling junction device of claim 1 , further comprising: an oxide layer on the free layer.
20. A method of manufacturing a magnetic tunnel junction device, the method comprising:
forming a seed layer on an electrode;
forming a pinned layer on the seed layer;
forming an anti-crystallized layer on the pinned layer;
performing heat treatment for crystallizing the pinned layer;
forming a polarization enhancing layer on the anti-crystallized layer;
forming a tunnel barrier layer on the polarization enhancing layer; and
forming a free layer on the tunnel barrier layer,
wherein
the seed layer comprises at least one amorphous material selected from CoFeX and CoFeXTa, and the X is an element selected from niobium (Nb), molybdenum (Mo), tungsten (W), chromium (Cr), and hafnium (Hf), and
wherein
the anti-crystallized layer comprises at least one of YCoB, YFeB, or YCoFeB and the Y comprises at least one element selected from tungsten (W), rhenium (Re), molybdenum (Mo), and tantalum (Ta), or
the anti-crystallized layer comprises at least one of ReFe, ReCo, or ReCoFe.
21. The method of claim 20 , wherein the heat treatment is performed at a temperature of 300° C. to 500° C.
22. The method of claim 20 , wherein a proportion of the X in the seed layer is 5 at % to 50 at %.
23. The method of claim 20 , wherein a thickness of the seed layer is 5 Å to 15 Å.
24. The method of claim 20 , wherein the seed layer is a single layer comprising CoFeXTa.
25. The method of claim 20 , wherein the forming of the seed layer comprises,
forming a first seed layer comprising CoFeX, on an electrode; and
forming a second seed layer comprising tantalum (Ta), on the first seed layer.
26. The method of claim 20 , wherein the anti-crystallized layer comprises YFeB, a proportion of FeB in the anti-crystallized layer is 20 at % to 60 at %, and a proportion of boron (B) in the FeB is 10 at % to 30 at %.
27. The method of claim 20 , wherein a thickness of the anti-crystallized layer is 1.5 Å to 10 Å.
28. The method of claim 20 , wherein the seed layer and the anti-crystallized layer are in an amorphous state at a temperature of 300° C. to 500° C.
29. The method of claim 20 , wherein the forming of the polarization enhancing layer comprises
forming a first polarization enhancing layer on the anti-crystallized layer; and
forming a second polarization enhancing layer on the first polarization enhancing layer, and
each of the first polarization enhancing layer and the second polarization enhancing layer comprises CoFeB, and a proportion of boron (B) in the second polarization enhancing layer is smaller than a proportion of boron (B) in the first polarization enhancing layer.
30. The method of claim 29 , wherein the proportion of boron (B) in the first polarization enhancing layer is 25 at % to 35 at %, and the proportion of boron (B) in the second polarization enhancing layer is 15 at % to 25 at %.
31. A memory device comprising:
a plurality of magnetic tunneling junction devices; and
a plurality of switching devices, each of the plurality of switching devices being connected to a respective one of plurality of magnetic tunneling junction devices,
wherein the respective one of the plurality of magnetic tunneling junction devices comprises:
a pinned layer having a first surface and a second surface opposite the first surface;
a seed layer contacting with the first surface of the pinned layer;
a free layer facing the second surface of the pinned layer;
a tunnel barrier layer between the pinned layer and the free layer; and
an anti-crystallized layer between the pinned layer and the tunnel barrier layer,
wherein the seed layer comprises at least one amorphous material selected from CoFeX and CoFeXTa, and the X is an element selected from niobium (Nb), molybdenum (Mo), tungsten (W), chromium (Cr), and hafnium (Hf), and
wherein
the anti-crystallized layer comprises at least one of YCoB, YFeB, or YCoFeB and the Y comprises at least one element selected from tungsten (W), rhenium (Re), molybdenum (Mo), and tantalum (Ta), or
the anti-crystallized layer comprises at least one of ReFe, ReCo, or ReCoFe.