Magnetic tunnel junction structure
View Patent ↗Disclosed herein is a thermally-assisted magnetic tunnel junction structure including a thermal barrier. The thermal barrier is composed of a cermet material in a disordered form such that the thermal barrier has a low thermal conductivity and a high electric conductivity. Compared to conventional magnetic tunnel junction structures, the disclosed structure can be switched faster and has improved compatibility with standard semiconductor fabrication processes.
1. A thermally-assisted magnetic tunnel junction structure, comprising:
a magnetic tunnel junction; and
a thermal barrier coupled to the magnetic tunnel junction, wherein the thermal barrier comprises a cermet material that comprises a ceramic component and a metallic component, the metallic component having a long range order that is no greater than 100 angstroms in the thermal barrier.
2. The thermally-assisted magnetic tunnel junction structure of claim 1 , wherein the magnetic tunnel junction comprises a free magnetic layer, a fixed magnetic layer, and a magnetic tunnel junction layer positioned between the free magnetic layer and the fixed magnetic layer, and the thermal barrier is attached to a major surface of the free magnetic layer of the magnetic tunnel junction.
3. The thermally-assisted magnetic tunnel junction structure of claim 1 , wherein the metallic component of the cermet has a long range order that is no greater than 200 angstroms.
4. The thermally-assisted magnetic tunnel junction structure of claim 1 , wherein the cermet material has a long range order that is no greater than 80 angstroms.
5. The thermally-assisted magnetic tunnel junction structure of claim 1 , wherein the thermal barrier has a thermal conductivity no greater than 2 W/mK.
6. The thermally-assisted magnetic tunnel junction structure of claim 1 , wherein the thermal barrier has an electric conductivity in the range of 1×10 4 S/m to 60×10 4 S/m at a temperature of 20° C.
7. The thermally-assisted magnetic tunnel junction structure of claim 1 , wherein the cermet material comprises a matrix base material with another material interspersed within or at a surface of the matrix base material.
8. A thermally-assisted magnetic random access memory structure, comprising:
a magnetic tunnel junction comprising a free magnetic layer, a fixed magnetic layer, and a tunnel junction layer positioned between the free magnetic layer and the fixed magnetic layer; and
a thermal barrier comprising a cermet material, and pinning the free magnetic layer below a temperature threshold and acting as a paramagnet at and above the temperature threshold when the thermal barrier is heated.
9. The thermally-assisted magnetic tunnel junction structure of claim 8 , wherein the cermet comprises a binary compound of a transition metal and nitrogen.
10. The thermally-assisted magnetic tunnel junction structure of claim 8 , wherein the cermet comprises a binary compound being comprised of one of SiO x , BO x , PO x , and AlO x .
11. The thermally-assisted magnetic tunnel junction structure of claim 8 , wherein the cermet comprises a ternary material X—Y—Z, where X is a transition metal; Y is one of Si, Al, and B; and Z is one of nitride, O—N, C—N, and P—N.
12. The thermally-assisted magnetic tunnel junction structure of claim 8 , wherein the cermet material comprises a composite of a transition metal and one of a nitride, oxynitride, and carbonitride.
13. A magnetic random access memory device, comprising:
a magnetic tunnel junction comprising a fixed magnetic layer, a free magnetic layer, and a magnetic tunnel junction layer; and
a thermal barrier adjacent to the magnetic tunnel junction and comprising a varistor having a non-linear current-voltage property.
14. The magnetic random access memory device of claim 13 , wherein the varistor comprises a cermet.
15. The magnetic random access memory device of claim 14 , wherein the thermal barrier comprises a material having the formula X a Y b Z c , wherein X is a transition metal, Y is selected from one of Group IIIA and Group IVA, and Z is selected from one of Group VA and Group VIA.
16. The magnetic random access memory device of claim 14 , wherein Y is one of Si, B, Al, and Ge.
17. The magnetic random access memory device of claim 14 , wherein Z is one of N and O.
18. The magnetic random access memory device of claim 14 , wherein X is one of Ir, Ru, Re, Pd, Pt, Rh, Co, and Ti.
19. The magnetic random access memory device of claim 14 , wherein X is one of an early transition metal and a late transition metal.
20. The magnetic random access memory device of claim 14 , wherein the thermal barrier comprises at least one of CoSiN and TiSiN.
21. The magnetic random access memory device of claim 14 , wherein the thermal barrier comprises an early transition metal nitride.
22. The magnetic random access memory device of claim 14 , the thermal barrier comprises an electrically conductive metal oxide and another chemical element.
23. The magnetic random access memory device of claim 22 , wherein the another chemical element is one of Si and O.
24. The magnetic random access memory device of claim 14 , wherein the thermal barrier comprises an oxynitride material.
25. The magnetic random access memory device of claim 14 , wherein the thermal barrier has a thermal conductivity no greater than 3 W/mK and an electric resistivity of at least 200 μΩ-cm at a temperature of 20° C.
26. The magnetic random access memory device of claim 25 , wherein the thermal barrier has a thermal conductivity no greater than 2 W/mK at a temperature of 20° C.
27. The magnetic random access memory device of claim 14 , wherein the thermal barrier has an electric resistivity of at least 1000 μΩ-cm at a temperature of 20° C.
28. A thermally-assisted magnetic tunnel junction structure, comprising:
a magnetic tunnel junction; and
a thermal barrier coupled to the magnetic tunnel junction, wherein the thermal barrier has a thermal conductivity no greater than 3 W/mK and an electric resistivity of at least 200 μΩ-cm at a temperature of 20° C.
29. The thermally-assisted magnetic tunnel junction structure of claim 28 , wherein the thermal barrier has a thermal conductivity no greater than 2 W/mK at a temperature of 20° C.
30. The thermally-assisted magnetic tunnel junction structure of claim 28 , wherein the thermal barrier has an electric resistivity of at least 1000 μΩ-cm at a temperature of 20° C.
31. The thermally-assisted magnetic tunnel junction structure of claim 28 , wherein the thermal barrier has a long range order that is no greater than 100 angstroms in the thermal barrier.
32. The thermally-assisted magnetic tunnel junction structure of claim 31 , wherein the thermal barrier comprises a metallic material and a dielectric material, and wherein the metallic material has a long range order no greater than 100 angstroms in the thermal barrier.
33. The thermally-assisted magnetic tunnel junction structure of claim 32 , wherein the metallic material has a long range order no greater than 80 angstroms.
34. A thermally-assisted magnetic tunnel junction structure, comprising:
a magnetic tunnel junction; and
a thermal barrier coupled to the magnetic tunnel junction, wherein the thermal barrier has a negative thermal coefficient of resistivity.
35. The thermally-assisted magnetic tunnel junction structure of claim 34 , wherein the thermal barrier has a thermal conductivity no greater than 3 W/mK and an electric resistivity of at least 200 μΩ-cm at a temperature of 20° C.
36. The thermally-assisted magnetic tunnel junction structure of claim 35 , wherein the thermal barrier has a thermal conductivity no greater than 2 W/mK at a temperature of 20° C.
37. The thermally-assisted magnetic tunnel junction structure of claim 35 , wherein the thermal barrier has an electric resistivity of at least 1000 μΩ-cm at a temperature of 20° C.
38. The thermally-assisted magnetic tunnel junction structure of claim 35 , wherein the thermal barrier comprises a varistor.
39. The thermally-assisted magnetic tunnel junction structure of claim 35 , wherein the thermal barrier comprises a cermet.