Spin orbit torque generating materials

Patent metadata

Field	Value
Publication number	US-10878985-B2
Application number	US-201715836421-A
Country	US
Kind code	B2
Filing date	Dec 8, 2017
Priority date	Dec 9, 2016
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

A material may include at least one of Bi x Se (1-x) , Bi x Te (1-x) , or Sb x Te (1-x) , where x is greater than 0 and less than 1. In some examples, the material exhibits a Spin Hall Angle of greater than 3.5 at room temperature. The disclosure also describes examples of devices that include a spin-orbit torque generating layer, in which the spin-orbit torque generating layer includes at least one of Bi x Se (1-x) , Bi x Te (1-x) , or Sb x Te (1-x) , where x is greater than 0 and less than 1. In some examples, the spin-orbit torque generating layer exhibits a Spin Hall Angle of greater than 3.5 at room temperature.

First claim

What is claimed is:

1. A material comprising:
Bi x Se (1-x) , wherein x is greater than 0, less than 1, and not 0.4, wherein the material comprises a concentration gradient of Bi, and wherein the material exhibits a Spin Hall Angle of greater than about 3.5 at room temperature.

2. The material of claim 1 , wherein the material exhibits a Spin Hall Angle of greater than about 20 at room temperature.

3. The material of claim 1 , wherein x is between about 0.45 and about 0.5.

4. The material of claim 1 , wherein x is about 0.47.

5. The material of claim 1 , further comprising a first region comprising a first composition comprising Bi x1 Se (1-x1) , a second region comprising a second composition comprising Bi x2 Se (1-x2) , and a third region comprising a third composition comprising Bi x3 Se (1-x3) , wherein the second region is between the first region and the third region, and wherein x2 is greater than x1 and greater than x3.

6. A device comprising:
a spin-orbit torque generating layer comprising at least one of Bi x Se (1-x) , Bi x Te (1-x) , or Sb x Te (1-x) , wherein x is greater than 0 and less than 1; and
a magnetic tunnel junction structure adjacent to the spin-orbit torque generating layer.

7. The device of claim 6 , wherein the spin-orbit torque generating layer exhibits a Spin Hall Angle of greater than about 3.5 at room temperature.

8. The device of claim 6 , wherein the at least one of Bi x Se (1-x) , Bi x Te (1-x) , or Sb x Te (1-x) comprises Bi x Se (1-x) , and wherein x is not 0.4.

9. The device of claim 6 , wherein the spin-orbit torque generating layer exhibits a Spin Hall Angle of greater than about 15 at room temperature.

10. The device of claim 6 , wherein x is greater than 0.4.

11. The device of claim 6 , wherein x is between about 0.45 and about 0.5.

12. The device of claim 6 , wherein the spin-orbit torque generating layer includes a concentration gradient of Bi or Sb.

13. The device of claim 6 , wherein the spin-orbit torque generating layer comprises a first region comprising at least one of Bi x1 Se (1-x1) , Bi x1 Te (1-x1 ), or Sb x1 Te (1-x1) , a second region comprising at least one of Bi x2 Se (1-x2) , Bi x2 Te (1-x2) , or Sb x2 Te (1-x2) , and a third region comprising at least one of Bi x3 Se (1-x3) , Bi x3 Te (1-x3) , or Sb x3 Te (1-x3) , wherein the second region is between the first region and the third region, and wherein x2 is greater than x1 and greater than x3.

14. The device claim 6 , further comprising a dopant not already present in the spin orbit torque generating layer, wherein the dopant comprises at least one of In, Sn, Bi, Se, Te, Au, Ag, Cu, Ti, V, Fe, Mn, Cr, Co, Ni, Gd, Tb, Sm, Nd, Eu, Dy, or Ho.

15. The device of claim 6 , wherein the magnetic tunnel junction structure comprises a free layer, a fixed layer, and an oxide layer between the free layer and the fixed layer, and wherein the spin-orbit torque generating layer is adjacent to the free layer.

16. The device of claim 15 , further comprising a substrate, wherein the spin-orbit torque generating layer is between the free layer and the substrate.

17. The device of claim 15 , further comprising a substrate, wherein the free layer is between the spin-orbit torque generating layer and the substrate.

18. The device of claim 17 , wherein the spin-orbit torque generating layer is on the free layer.

19. The device of claim 15 , further comprising a silicon substrate.

20. The device of claim 15 , wherein the spin-orbit torque generating layer comprises at least one of Bi x Se (1-x) , Bi x Te (1-x) , and wherein the concentration of Bi is less in a portion of the spin-orbit torque generating layer nearer to the free layer.

21. The device of claim 6 , wherein an average grain size of the spin-orbit torque generating layer is between about 5 nanometers and about 15 nanometers.

22. The device of claim 6 , wherein a crystalline axis of the spin-orbit torque generating layer is canted at a non-perpendicular angle to a major surface of the spin-orbit torque generating layer.

23. The device of claim 6 , wherein the spin-orbit torque generating layer defines a thickness between about 4 nm and about 40 nm.

24. The device of claim 23 , wherein the spin-orbit torque generating layer defines an average surface roughness of less than or equal to about 0.6 nm.

25. The device of claim 6 , wherein the spin-orbit torque generating layer defines an average surface roughness of less than about 5% of a thickness of the spin-orbit torque generating layer.

26. A material comprising:
a spin-orbit torque generating layer comprising a Spin Hall effect material having an average grain size of between about 3 nanometers and about 15 nanometers.

27. The material of claim 26 , wherein the Spin Hall effect material comprises at least one of Bi x Se (1-x) , Bi x Te (1-x) , or Sb x Te (1-x) , wherein x is greater than 0 and less than 1.

28. The material of claim 27 , wherein the Spin Hall effect material comprises Bi x Se (1-x) , wherein x is greater than 0, less than 1, and not 0.4.

29. A method comprising:
depositing at least one of Bi x Se (1-x) , Bi x Te (1-x) , or Sb x Te (1-x) on a substrate using at least one of sputtering, atomic layer deposition, chemical vapor deposition, or electrochemical deposition to form a spin-orbit torque generating layer, wherein x is greater than 0 and less than 1; and
forming a magnetic tunnel junction structure adjacent to the spin-orbit torque generating layer.

30. The method of claim 29 , further comprising:
depositing the at least one of Bi x Se (1-x) , Bi x Te (1-x) , or Sb x Te (1-x) on a substrate using magnetron sputtering.

31. The method of claim 30 , wherein the substrate comprises a semiconductor.

32. The method of claim 31 , wherein the substrate comprises Si or an Si alloy.

33. The method of claim 32 , wherein the substrate further comprises at least one of a silicon oxide layer or an MgO layer on the Si or Si alloy.

34. The method of claim 29 , wherein a target material comprises a mixture or alloy of Bi and Se.

Assignees

• Univ Minnesota

Inventors

• Wang Jian-Ping
• Dc Mahendra
• Jamali Mahdi
• Mkhoyan Andre
• Hickey Danielle

Classifications

• H10N50/85

  Materials of the active region · CPC title

• H01F10/30

  characterised by the composition of the intermediate layers {, e.g. seed, buffer, template, diffusion preventing, cap layers (H01F10/06 and H01F10/32 take precedence)} · CPC title

• H01F10/329 Primary

  Spin-exchange coupled multilayers wherein the magnetisation of the free layer is switched by a spin-polarised current, e.g. spin torque effect · CPC title

• G11C11/1675

  Writing or programming circuits or methods · CPC title

• H01F10/123

  having a L10 crystallographic structure, e.g. [Co,Fe][Pt,Pd] thin films · CPC title