IP Library Granted Patent US 7,885,105
Granted Patent B2
US 7,885,105 · App. 12/054,536 · Granted Feb 8, 2011

Magnetic tunnel junction cell including multiple vertical magnetic domains

Assignee: QUALCOMM Incorporated
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Quick Facts
Patent No.
US 7,885,105
App. No.
12/054,536
Granted
Feb 8, 2011
Kind
B2
Abstract

Magnetic tunnel junction cell including multiple vertical domains. In an embodiment, a magnetic tunnel junction (MTJ) structure is disclosed. The MTJ structure includes an MTJ cell. The MTJ cell includes multiple vertical side walls. Each of the multiple vertical side walls defines a unique vertical magnetic domain. Each of the unique vertical magnetic domains is adapted to store a digital value.

Claims (36)

1. A magnetic tunnel junction (MTJ) structure comprising:

a MTJ cell comprising multiple vertical side walls, each of the multiple vertical side walls defining a unique vertical magnetic domain, each of the unique vertical magnetic domains adapted to store a digital value.

2. The MTJ structure of claim 1 , wherein a first of the vertical side walls is separated from a second of the vertical side walls by a distance that is less than a height of the first vertical side wall.

3. The MTJ structure of claim 1 , wherein the MTJ cell further comprises a center electrode extending vertically between the multiple vertical side walls.

4. The MTJ structure of claim 3 , wherein a thickness of the center electrode is approximately half of a difference between a width of the MTJ cell minus a width of two opposing side walls of the multiple vertical side walls.

5. The MTJ structure of claim 1 , wherein the MTJ cell comprises a first vertical side wall having a first magnetic domain, a second vertical sidewall having a second magnetic domain and a third vertical sidewall having a third magnetic domain.

6. The MTJ structure of claim 5 , wherein the MTJ cell further comprises a bottom wall coupled to the multiple vertical side walls, the bottom wall having a fourth magnetic domain.

7. The MTJ structure of claim 6 , further comprising four terminal structures, wherein three of the four terminal structures are coupled to the vertical side walls and a fourth of the four terminal structures is coupled to the bottom wall.

8. The MTJ structure of claim 1 , wherein the MTJ cell is U-shaped.

9. The MTJ structure of claim 1 , wherein the MTJ cell comprises four vertical side walls in a substantially rectangular shape.

10. The MTJ structure of claim 9 , wherein the MTJ cell further comprises a bottom wall coupled to the four vertical side walls.

11. The MTJ structure of claim 10 , wherein the MTJ structure further comprises six terminal structures.

12. A device comprising:

a single magnetic tunnel junction (MTJ) cell adapted to store multiple digital values, wherein at least one of the multiple digital values is stored using a vertical magnetic field; and

multiple terminals coupled to the MTJ cell.

13. The device of claim 12 , further comprising a transistor coupled to a first of the multiple terminals, the transistor also coupled to a data write line and to a first source line.

14. The device of claim 13 , further comprising a second transistor coupled to a second of the multiple terminals, the second transistor coupled to the data write line and coupled to a second source line.

15. The device of claim 14 , further comprising a third transistor coupled to a third of the multiple terminals, the third transistor coupled to the data write line and coupled to a third source line.

16. The device of claim 15 , wherein the first of the multiple terminals is coupled to a first sidewall of the MTJ cell, the second of the multiple terminals is coupled to a second sidewall of the MTJ cell, and the third of the multiple terminals is coupled to a bottom wall of the MTJ cell.

17. The device of claim 16 , further comprising a fourth of the multiple terminals coupled to a bit line.

18. A method of fabricating a device, the method comprising:

performing a deep trench photo and etch process to create a deep trench in a substrate;

depositing a bottom electrode into the deep trench;

depositing layers to form a magnetic tunnel junction (MTJ) structure including a fixed layer, a tunnel barrier, and a free layer, at least a first portion of the MTJ structure coupled to the bottom electrode;

depositing a top electrode onto at least a second portion of the MTJ structure; and

performing magnetic anneal process on the MTJ structure in a horizontal direction and in a vertical direction, the horizontal direction substantially parallel to a plane of the substrate and the vertical direction substantially normal to the plane of the substrate;

wherein a first portion of the free layer has a first magnetic domain in the vertical direction and wherein a second portion of the free layer has a second magnetic domain in the horizontal direction.

19. The method of claim 18 , further comprising performing an inter-layer dielectric (ILD) deposit and performing a chemical mechanical polish (CMP) process.

20. The method of claim 19 , further comprising performing photoresist, etching, filling, and CMP processes on a via coupled to the MTJ.

21. The method of claim 18 , wherein the MTJ structure includes a first sidewall in the vertical direction and a second sidewall in the vertical direction.

22. The method of claim 21 , further comprising:

depositing a cap film layer;

performing a process to etch, fill, and polish a bottom via; and

depositing an inter-layer dielectric layer.

23. The method of claim 18 , wherein the MTJ structure has a U-shape.

24. The method of claim 18 , wherein the trench has a depth greater than a height of a sidewall of the MTJ structure, wherein the height of the sidewall is greater than a length of the trench and greater than a width of the trench.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 25, 2008
From: LI, XIA; KANG, SEUNG H.; ZHU, XIAOCHUN
To: QUALCOMM INCORPORATED
Reel/Frame 020695/0259 →
Continuity (1)
Related Publication 20090243009A1 · Oct 1, 2009