IP Library › Granted Patent US 50,331
Granted Patent E1
US 50,331 · App. 17/658,470 · Granted Mar 4, 2025

Magnetoresistive stack and method of fabricating same

Inventors: Renu Whig (Chandler, AZ); Jijun Sun (Chandler, AZ); Nicholas Rizzo (Gilbert, AZ); Jon Slaughter (Slingerlands, NY); Dimitri Houssameddine (Latham, NY); Frederick Mancoff (Chandler, AZ)
Assignee: Everspin Technologies, Inc.
H10N50/01G11C11/161H10N50/10H10N50/80H10N50/85
View Patent ↗
Loading inventors, assignments & file history…
Monitor This Case
Get email alerts when status or documents change.
Order Certified Copies
Most orders are placed with the USPTO same day — all within 24 business hours.
Order via The Patent Place →
Pre-filled with this patent's details
Quick Facts
Patent No.
US 50,331
App. No.
17/658,470
Granted
Mar 4, 2025
Kind
E1
Abstract

A magnetoresistive element (e.g., a spin-torque magnetoresistive memory element) includes a fixed magnetic layer, a free magnetic layer, having a high-iron alloy interface region located along a surface of the free magnetic layer, wherein the high-iron alloy interface region has at least 50% iron by atomic composition, and a first dielectric, disposed between the fixed magnetic layer and the free magnetic layer. The magnetoresistive element further includes a second dielectric, having a first surface that is in contact with the surface of the free magnetic layer, and an electrode, disposed between the second dielectric and a conductor. The electrode includes: (i) a non-ferromagnetic portion having a surface that is in contact with a second surface of the second dielectric, and (ii) a second portion having at least one ferromagnetic material disposed between the non-ferromagnetic portion of the electrode and the conductor.

Claims (74)

1. A magnetoresistive device, comprising:

a free magnetic layer having a first side and a second side;

a first electrode positioned on the first side of the free magnetic layer;

a second electrode positioned on the second side of the free magnetic layer;

a first dielectric layer in contact with the first electrode and the first side of the free magnetic layer; and

a second dielectric layer in contact with the second electrode and the second side of the free magnetic layer;

wherein an interface region of the free magnetic region on the second side has a higher iron content than an interface region of the free magnetic layer on the first side.

2. The device of claim 1 , wherein the interface region of the free magnetic layer on the second side has an iron content of greater than 20 percent by atomic composition, and the interface region of the free magnetic layer on the first side has an iron content of less than 20 percent by atomic composition.

3. The device of claim 1 , wherein the interface region of the free magnetic layer on the second side has an iron content of greater than 20 percent by atomic composition, and the interface region of the free magnetic layer on the first side has an iron content of approximately five percent by atomic composition.

4. The device of claim 1 , wherein the interface region of the free magnetic layer on the second side has an iron content of greater than 50 percent by atomic composition.

5. The device of claim 1 , wherein the interface region of the free magnetic layer on the second side has an iron content of greater than 20 percent by atomic composition and a boron content of between 14 percent and 20 percent by atomic composition, and the interface region of the free magnetic layer on the first side has an iron content of less than 20 percent by atomic composition and a boron content of greater than 20 percent by atomic composition.

6. The device of claim 1 , wherein the interface region of the free magnetic layer on the second side has an iron content of greater than 20 percent by atomic composition and a boron content of between 14 percent and 20 percent by atomic composition, and the interface region of the free magnetic layer on the first side has an iron content of 5 percent by atomic composition and a boron content of 25 percent by atomic composition.

7. The device of claim 1 , wherein at least one of the first electrode and the second electrode is a fixed magnetic layer.

8. The device of claim 1 , wherein the first electrode is a first fixed magnetic layer and the second electrode is a second fixed magnetic layer.

9. The device of claim 8 , wherein at least one of the first fixed magnetic layer and the second fixed magnetic layer includes a synthetic antiferromagnetic structure.

10. The device of claim 8 , wherein both the first fixed magnetic layer and the second fixed magnetic layer include a synthetic antiferromagnetic structure.

11. The device of claim 1 , wherein the first dielectric layer and the second dielectric layer include magnesium oxide (MgO).

12. The device of claim 1 , wherein the free magnetic layer includes two ferromagnetic layers coupled together by a layer of a non-ferromagnetic transition metal.

13. A magnetoresistive device, comprising:

a free magnetic layer including a first surface and a second surface, wherein a region of the free magnetic layer that includes the second surface has a higher iron content than a region of the free magnetic layer that includes the first surface;

a first fixed magnetic layer positioned on one side of the free magnetic layer;

a second fixed magnetic layer positioned on an opposite side of the free magnetic layer;

a first intermediate layer in contact with the first fixed magnetic layer and the first surface of the free magnetic layer; and

a second intermediate layer in contact with the second fixed magnetic layer and the second surface of the free magnetic layer.

14. The device of claim 13 , wherein the region of the free magnetic layer that includes the second surface has an iron content of greater than 20 percent by atomic composition, and the region of the free magnetic layer that includes the first surface has an iron content of less than 20 percent by atomic composition.

15. The device of claim 13 , wherein the region of the free magnetic layer that includes the second surface has an iron content of greater than 20 percent by atomic composition, and the region of the free magnetic layer that includes the first surface has an iron content of approximately five percent by atomic composition.

16. The device of claim 13 , wherein the region of the free magnetic layer that includes the second surface has an iron content of greater than 50 percent by atomic composition.

17. The device of claim 13 , wherein the region of the free magnetic layer that includes the second surface has an iron content of greater than 20 percent by atomic composition and a boron content of between 14 percent and 20 percent by atomic composition, and the region of the free magnetic layer that includes the first surface has an iron content of less than 20 percent by atomic composition and a boron content of greater than 20 by atomic composition.

18. The device of claim 13 , wherein the region of the free magnetic layer that includes the second surface has an iron content of greater than 20 percent by atomic composition and a boron content of between 14 percent and 20 percent by atomic composition, and the region of the free magnetic layer that includes the first surface has an iron content of 5 percent by atomic composition and a boron content of 25 percent by atomic composition.

19. The device of claim 13 , wherein at least one of the first fixed magnetic layer and the second fixed magnetic layer includes a synthetic antiferromagnetic structure.

20. The device of claim 13 , wherein each of the first fixed magnetic layer and the second fixed magnetic layer includes a synthetic antiferromagnetic structure.

21. A magnetoresistive device, comprising:

a free magnetic layer having a first side and a second side;

a first electrode positioned proximate the first side of the free magnetic layer;

a second electrode positioned proximate the second side of the free magnetic layer;

a first dielectric layer in contact with the first electrode and the first side of the free magnetic layer; and

a second dielectric layer in contact with the second electrode and the second side of the free magnetic layer.

22. The device of claim 21 , wherein at least one of the first electrode and the second electrode is a fixed magnetic layer.

23. The device of claim 21 , wherein the first electrode is a fixed magnetic layer.

24. The device of claim 21 , wherein at least one of the first dielectric layer and the second dielectric layer include magnesium oxide (MgO).

25. The device of claim 21 , wherein at least one of the first dielectric layer and the second dielectric layer includes at least one of magnesium and oxygen.

26. The device of claim 21 , wherein each of the first dielectric layer and the second dielectric layer includes at least one of magnesium and oxygen.

27. The device of claim 21 , wherein each of the first dielectric layer and the second dielectric layer includes magnesium oxide (MgO).

28. A magnetoresistive device, comprising:

a free magnetic layer including a first surface and a second surface;

a fixed magnetic layer positioned proximate a first side of the free magnetic layer;

a first intermediate layer in contact with the fixed magnetic layer and the first surface of the free magnetic layer; and

a second intermediate layer in contact with the second surface of the free magnetic layer.

29. The device of claim 28 , wherein at least one of the first intermediate layer and the second intermediate layer includes a dielectric material.

30. The device of claim 28 , wherein each of the first intermediate layer and the second intermediate layer includes a dielectric material.

31. The device of claim 28 , wherein at least one of the first intermediate layer and the second intermediate layer includes at least one of magnesium and oxygen.

32. The device of claim 28 , wherein each of the first intermediate layer and the second intermediate layer includes at least one of magnesium and oxygen.

33. The device of claim 28 , wherein at least one of the first intermediate layer and the second intermediate layer includes magnesium oxide (MgO).

34. The device of claim 28 , wherein each of the first intermediate layer and the second intermediate layer includes magnesium oxide (MgO).

35. A magnetoresistive device, comprising:

a fixed magnetic layer;

a free magnetic layer, wherein the free magnetic layer includes perpendicular magnetic anisotropy;

a first dielectric layer disposed between the fixed magnetic layer and the free magnetic layer, wherein the first dielectric layer includes a surface in contact with a surface of the free magnetic layer;

a conductor including electrically conductive material; and

a second dielectric layer disposed between the free magnetic layer and the conductor.

36. The device of claim 35 , wherein at least one of the first dielectric layer and the second dielectric layer includes at least one of magnesium and oxygen.

37. The device of claim 35 , wherein each of the first dielectric layer and the second dielectric layer includes at least one of magnesium and oxygen.

38. The device of claim 35 , wherein at least one of the first dielectric layer and the second dielectric layer includes magnesium oxide (MgO).

39. The device of claim 35 , wherein each of the first dielectric layer and the second dielectric layer includes magnesium oxide (MgO).

40. A magnetoresistive device, comprising:

a magnetic layer, wherein magnetic layer includes perpendicular magnetic anisotropy;

a fixed magnetic layer;

a first dielectric layer disposed between the fixed magnetic layer and the magnetic layer, wherein the first dielectric layer includes a surface in contact with a surface of the magnetic layer;

a conductor including electrically conductive material; and

a second dielectric layer disposed between the magnetic layer and the conductor.

41. The device of claim 40 , wherein the magnetic layer includes two or more ferromagnetic layers coupled together by a layer of a non-ferromagnetic material.

42. The device of claim 40 , wherein the conductor includes a second fixed magnetic layer.

43. The device of claim 42 , wherein at least one of the first fixed magnetic layer and the second fixed magnetic layer includes a synthetic antiferromagnetic structure.

44. The device of claim 40 , wherein the first dielectric layer and the second dielectric layer include magnesium oxide (MgO).

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 18, 2024
From: WHIG, RENU; SLAUGHTER, JON; RIZZO, NICHOLAS; SUN, JIJUN; MANCOFF, FREDERICK; HOUSSAMEDDINE, DIMITRI
To: EVERSPIN TECHNOLOGIES, INC.
Reel/Frame 067758/0929 →
Continuity (7)
Continuation 16230031 · Dec 21, 2018
Continuation 15941153 · Mar 30, 2018
Continuation 15400889 · Jan 6, 2017
Division 14860657 · Sep 21, 2015
Continuation 14219532 · Mar 19, 2014
Division 13158171 · Jun 10, 2011
Reissue 16419165 · May 22, 2019
References Cited (87)
US 5768181A · Zhu et al. · 1998 [cited by applicant]
US 5801984A · Parkin · 1998 [cited by applicant]
US 6122150A · Gill · 2000 [cited by applicant]
US 6233172B1 · Chen · 2001 [cited by examiner]
US 6469926B1 · Chen · 2002 [cited by applicant]
US 6544801B1 · Slaughter et al. · 2003 [cited by applicant]
US 6714444B2 · Huai et al. · 2004 [cited by applicant]
US 6750068B2 · Chen · 2004 [cited by applicant]
US 6778427B2 · Odagawa et al. · 2004 [cited by applicant]
US 6831312B2 · Slaughter et al. · 2004 [cited by applicant]
US 6885065B2 · Liang · 2005 [cited by examiner]
US 7018725B2 · Odagawa et al. · 2006 [cited by applicant]
US 7067331B2 · Slaughter et al. · 2006 [cited by applicant]
US 7098495B2 · Sun et al. · 2006 [cited by applicant]
US 7241631B2 · Huai et al. · 2007 [cited by applicant]
US 7382643B2 · Ashida et al. · 2008 [cited by applicant]
US 7390529B2 · Li et al. · 2008 [cited by applicant]
US 7430135B2 · Huai et al. · 2008 [cited by applicant]
US 7528457B2 · Horng et al. · 2009 [cited by applicant]
US 7595520B2 · Horng et al. · 2009 [cited by applicant]
US 7605437B2 · Mancoff et al. · 2009 [cited by applicant]
US 7672093B2 · Horng et al. · 2010 [cited by applicant]
US 7932571B2 · Rizzo et al. · 2011 [cited by applicant]
US 8565013B2 · Bessho et al. · 2013 [cited by applicant]
US 8686484B2 · Whig et al. · 2014 [cited by applicant]
US 8709619B2 · Girt · 2014 [cited by applicant]
US 9159906B2 · Whig et al. · 2015 [cited by applicant]
US 9419208B2 · Whig et al. · 2016 [cited by applicant]
US 9455400B2 · Cao et al. · 2016 [cited by applicant]
US 9553258B2 · Whig et al. · 2017 [cited by applicant]
US 9947865B2 · Whig et al. · 2018 [cited by applicant]
US 10199574B2 · Whig et al. · 2019 [cited by applicant]
US 10347828B2 · Whig · 2019 [cited by examiner]
US 10622554B2 · Whig · 2020 [cited by examiner]
US 20030030119A1 · Higgins et al. · 2003 [cited by applicant]
US 20040041183A1 · Slaughter · 2004 [cited by examiner]
US 20040070312A1 · Penunuri et al. · 2004 [cited by applicant]
US 20040091744A1 · Carey et al. · 2004 [cited by applicant]
US 20040145850A1 · Fukumoto et al. · 2004 [cited by applicant]
US 20040257719A1 · Ohba et al. · 2004 [cited by applicant]
US 20050219769A1 · Shimura et al. · 2005 [cited by applicant]
US 20050264954A1 · Li · 2005 [cited by applicant]
US 20060018057A1 · Huai · 2006 [cited by applicant]
US 20060104110A1 · Sun et al. · 2006 [cited by applicant]
US 20060098354A1 · Parkin · 2006 [cited by applicant]
US 20060114618A1 · Hosomi et al. · 2006 [cited by applicant]
US 20060141640A1 · Huai et al. · 2006 [cited by applicant]
US 20060180839A1 · Fukumoto et al. · 2006 [cited by applicant]
US 20060221680A1 · Hosotani · 2006 [cited by applicant]
US 20070076469A1 · Ashida · 2007 [cited by examiner]
US 20070111332A1 · Zhao et al. · 2007 [cited by applicant]
US 20070182279A1 · Kawano et al. · 2007 [cited by applicant]
US 20070228501A1 · Nakamura et al. · 2007 [cited by applicant]
US 20080023740A1 · Horng et al. · 2008 [cited by applicant]
US 20080074805A1 · Ikarashi et al. · 2008 [cited by applicant]
US 20080179699A1 · Horng · 2008 [cited by examiner]
US 20080182342A1 · Parkin · 2008 [cited by applicant]
US 20080299679A1 · Zhao et al. · 2008 [cited by applicant]
US 20090027810A1 · Horng et al. · 2009 [cited by applicant]
US 20090108383A1 · Horng · 2009 [cited by examiner]
US 20100148167A1 · Whig et al. · 2010 [cited by applicant]
US 20100176470A1 · Horng et al. · 2010 [cited by applicant]
US 20100195380A1 · Wang et al. · 2010 [cited by applicant]
US 20100302690A1 · Worledge · 2010 [cited by applicant]
US 20100320550A1 · Abraham et al. · 2010 [cited by applicant]
US 20110278993A1 · Iwamoto · 2011 [cited by applicant]
US 20120229003A1 · Ito · 2012 [cited by applicant]
US 20140130319A1 · Iwamoto · 2014 [cited by applicant]
US 20140167565A1 · Iwamoto · 2014 [cited by applicant]
US 20150280107A1 · Hori et al. · 2015 [cited by applicant]
US 20160013401A1 · Whig et al. · 2016 [cited by applicant]
US 20180226574A1 · Whig et al. · 2018 [cited by applicant]
US 20190123268A1 · Whig et al. · 2019 [cited by applicant]
EP 1073071A2 · 2001 [cited by examiner]
JP 2000332317 · 2000 [cited by applicant]
JP 2000332317A · 2000 [cited by applicant]
JP 2011124738A · 2011 [cited by applicant]
WO WO03032338A1 · 2003 [cited by examiner]
EPO Examination Report, mailed Apr. 13, 2017, 4 pages. [cited by applicant]
Nakamura et al., “Current-Induced Magnetization Switching in Two Types of Nanopillar with Dual Fixed Layers”, Japanese J. of Applied Physics, vol. 45, No. SA, pp. 3846-3849. [cited by applicant]
Office Action issued in Chinese Application corresponding to PCT/US2012/041354, mailed Feb. 23, 2016, 17 pages. [cited by applicant]
Office Action issued in Chinese Application corresponding to PCT/US2012/041354, mailed Sep. 2, 2016, 7 pages. [cited by applicant]
Partial Supplementary European Search Report, issued Dec. 2, 2014, in connection with EP Application 12796925.1, 6 pages. [cited by applicant]
USPTO, International Searching Authority, International Search Report, mailed Aug. 9, 2012, in connection with PCT/US2012/041354. [cited by applicant]
Fuchs et al., “Adjustable Spin Torque in Magnetic Tunnel Junctions with Two Fixed Layers”, App. Physics Letters 85, 2005, pp. 152509-1 to 152509-3. [cited by applicant]
Berger, L., “Multilayer Configuration for Experiments of Spin Precession Induced by a DC Current”, Journal of Applied Physics, vol. 93, No. 10, 2003, pp. 7693-7695. [cited by applicant]
Extended European Search Report issued in EP application No. 12796925, dated Mar. 23, 2015, 10 pages. [cited by applicant]