Hybrid memory cell for spin-polarized electron current induced switching and writing/reading process using such memory cell

• US 7,630,231 B2
• Filed: 08/27/2007
• Issued: 12/08/2009
• Est. Priority Date: 12/30/2004
• Status: Active Grant

• Current Assignee: Altis Semiconductor (Altis International), Centre National De La Recherche Scientifique, Infineon Technologies AG, Universite Paris - Sud
• Original Assignee: Altis Semiconductor (Altis International), Centre National De La Recherche Scientifique, Infineon Technologies AG, Universite Paris - Sud
• Inventors: Nakatani, Yoshinobu, Miltat, Jacques, Klostermann, Ulrich
• Primary Examiner(s): Nguyen; Dang T
• Application Number:
  US11/845,525
• Publication Number:
  US 20080094881A1
• Time in Patent Office: 834 Days
• Field of Search: 365/158, 365/171, 365/173, 365/225.5, 365/63, 365/230.07, 257/295
• US Class Current: 365/158
• CPC Class Codes: G11C 11/16 using elements in which the storage effect is based on magnetic spin effect

Abstract

A magnetoresistive hybrid memory cell includes first and second stacked structures. The first stacked structure includes a magnetic tunnel junction including first and second magnetic regions stacked in a parallel, overlying relationship separated by a layer of non-magnetic material, wherein the first magnetic region has a fixed first magnetic moment vector and the second magnetic region has a free second magnetic moment vector that is switchable between the same and opposite directions with respect to the fixed first magnetic moment vector. The second stacked structure is at least partly arranged in a lateral relationship with respect to the first stacked structure and includes a third magnetic region having a fixed third magnetic moment vector and the second magnetic region. The first and second structures are arranged between at least two electrodes in electrical contact therewith.

Claims

1. A magnetoresistive hybrid memory cell, comprising:

a first stacked structure comprising a magnetic tunnel junction including first and second magnetic regions stacked in a parallel, overlying relationship separated by a layer of non-magnetic material, wherein the first magnetic region has a fixed first magnetic moment vector and the second magnetic region has a free second magnetic moment vector which is switchable between a same and opposite directions with respect to the fixed first magnetic moment vector of the first magnetic region;

a second stacked structure arranged at least partly in a lateral relationship to the first stacked structure and comprising a third magnetic region having a fixed third magnetic moment vector and the second magnetic region; and

at least two electrodes, wherein the first and second structures are arranged between, and are in electrical contact with, the at least two electrodes,

wherein the first magnetic moment vector of the first magnetic region is aligned parallel with respect to the second magnetic moment vector of the second magnetic region.

2. The magnetoresistive hybrid memory cell of claim 1, wherein the fixed third magnetic moment vector of the third magnetic region is aligned parallel with respect to the free second magnetic moment vector of the second magnetic region.

3. The magnetoresistive hybrid memory cell of claim 2, wherein the first, second and third magnetic moment vectors are perpendicularly aligned with respect to a bottom surface of the first and second stacked structures.

4. The magnetoresistive hybrid memory cell of claim 1, wherein one of the at least two electrodes is arranged on one side of the first and second stacked structures and is a common electrode connecting the first and second stacked structures.

5. The magnetoresistive hybrid memory cell of claim 4, wherein the common electrode is positioned adjacent the second magnetic region.

6. The magnetoresistive hybrid memory cell of claim 5, wherein the at least two electrodes includes separate electrodes for each of the first and second stacked structures, the separate electrodes being respectively arranged on the first and second stacked structures on a side opposite the common electrode.

7. The magnetoresistive hybrid memory cell of claim 1, wherein the at least two electrodes includes first and second electrodes on opposite sides of the first stacked structure, and third and fourth electrodes on opposite sides of the second stacked structure, the third and fourth electrodes being separate from the first and second electrodes.

8. The magnetoresistive hybrid memory cell of claim 1, wherein the first magnetic region comprises:

a first ferromagnetic layer, a separating layer, a second ferromagnetic layer and an antiferromagnetic layer.

9. The magnetoresistive hybrid memory cell of claim 8, wherein the separating layer comprises ruthenium (Ru).

10. A method of writing to and reading from a magnetoresistive hybrid memory cell, the method comprising:

providing a magnetoresistive hybrid memory cell comprising;

a first stacked structure comprising a magnetic tunnel junction including first and second magnetic regions stacked in a parallel, overlying relationship separated by a layer of non-magnetic material, wherein the first magnetic region being provided with a fixed first magnetic moment vector and the second magnetic region being provided with a free second magnetic moment vector which is switchable between a same and an opposite direction with respect to the fixed first magnetic moment vector of the first magnetic region;

a second stacked structure arranged at least partly in a lateral relationship to the first stacked structure and comprising a third magnetic region being provided with a fixed third magnetic moment vector and the second magnetic region; and

at least two electrodes, wherein the first and second structures are arranged between, and are in electrical contact with, the at least two electrodes;

applying a writing voltage pulse resulting in a writing current pulse flowing through the second magnetic region for switching of its free magnetic moment vector to electrodes on both sides of only the second stacked structure; and

applying a reading voltage pulse resulting in a reading current pulse flowing through the magnetic tunnel junction to electrodes on both sides of only the first stacked structure.

11. The method of claim 10, wherein the writing voltage pulse is applied so as to produce a coherent rotation over half a full turn of the free second magnetic moment vector in total.

12. The method of claim 10, wherein the polarity of the writing voltage pulse is applied so as to produce a parallel or antiparallel alignment of the magnetization direction of the first and second magnetic regions.

13. The method of claim 10, wherein the fixed magnetic moment vector of the third magnetic region is perpendicularly aligned with respect to the free magnetic moment vector of the second magnetic region.

14. The method of claim 10, wherein one of the at least two electrodes is arranged on one side of the first and second stacked structures and is a common electrode connecting the first and second stacked structures.

15. The method of claim 14, wherein the common electrode is positioned adjacent the second magnetic region.

16. The method of claim 15, wherein the at least two electrodes includes separate electrodes for each of the first and second stacked structures, the separate electrodes being respectively arranged on the first and second stacked structures on a side opposite the common electrode.

17. The method of claim 10, wherein the at least two electrodes includes first and second electrodes disposed on opposite sides of the first stacked structure, and third and fourth electrodes disposed on opposite sides of the second stacked structure, the third and fourth electrodes being separate from the first and second electrodes.

18. The method of claim 10, wherein the first magnetic moment vector of the first magnetic region is aligned parallel with respect to the second magnetic moment vector of the second magnetic region.

19. The method of claim 18, wherein the fixed magnetic moment vector of the third magnetic region is aligned in parallel to the free magnetic moment vector of the second magnetic region.

20. The method of claim 19, wherein the first, second and third magnetic moment vectors are perpendicularly aligned with respect to bottom surfaces of said first and second stacked structures.

21. The method of claim 20, wherein the separating layer comprises ruthenium (Ru).

22. The method of claim 10, wherein the first magnetic region comprises a first ferromagnetic layer, a separating layer, a second ferromagnetic layer and an antiferromagnetic layer.

23. A method of writing to and reading from a magnetoresistive hybrid memory cell, the method comprising:

providing a magnetoresistive hybrid memory cell comprising;

a first stacked structure comprising a magnetic tunnel junction including first and second magnetic regions stacked in a parallel, overlying relationship separated by a layer of non-magnetic material, wherein the first magnetic region being provided with a fixed first magnetic moment vector and the second magnetic region being provided with a free second magnetic moment vector which is switchable between a same and an opposite direction with respect to the fixed first magnetic moment vector of the first magnetic region;

a second stacked structure arranged at least partly in a lateral relationship to the first stacked structure and comprising a third magnetic region having a fixed third magnetic moment vector and the second magnetic region; and

at least two electrodes, wherein the first and second structures are arranged between, and are in electrical contact with the at least two electrodes;

applying a writing voltage pulse resulting in a writing current pulse flowing through the second magnetic region for switching of its free magnetic moment vector to electrodes on both sides of only the second stacked structure, wherein the switching voltage pulse is applied so as to produce a coherent rotation over half a full turn of the free second magnetic moment vector in total, the switching time being provided with a slow rise time and a fast fall time; and

applying a reading voltage pulse resulting in a reading current pulse flowing through the magnetic tunnel junction to electrodes on both sides of only the first stacked structure.

24. The method of claim 23, wherein the first magnetic moment vector of the first magnetic region is aligned parallel with respect to the second magnetic moment vector of the second magnetic region.

25. The method of claim 24, wherein the fixed magnetic moment vector of the third magnetic region is aligned in parallel to the free magnetic moment vector of the second magnetic region.