MAGNETIC RANDOM ACCESS MEMORY AND METHOD OF MANUFACTURING THE SAME

• US 20100046288A1
• Filed: 10/22/2007
• Published: 02/25/2010
• Est. Priority Date: 12/06/2006
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Honjou, Hiroaki, Ohshima, Norikazu, Suzuki, Tetsuhiro
• Granted Patent: US 8,300,456 B2
• Time in Patent Office: Days
• US Class Current: 365/171
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: G11C 11/1675 Writing or programming circuits or methods
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

An MRAM according to the present invention has a pinned layer 60 and a magnetic recording layer 40 connected to the pinned layer 60 through a tunnel barrier layer 50. The magnetic recording layer 40 has a first free layer 10, a second free layer 30 being in contact with the tunnel barrier layer 50, and an intermediate layer 20 provided between the first free layer 10 and the second free layer 30. The first free layer 10 includes a magnetization switching region 13, a first magnetization fixed region 11 and a second magnetization fixed region 12. The magnetization switching region 13 has reversible magnetization and overlaps the second free layer 30. The first magnetization fixed region 11 is connected to a first boundary B1 of the magnetization switching region 13 and its magnetization orientation is fixed in a first direction. Whereas, the second magnetization fixed region 12 is connected to a second boundary B2 of the magnetization switching region 13 and its magnetization orientation is fixed in a second direction. The first direction and second direction both are toward the magnetization switching region 13 or away from the magnetization switching region 13. The intermediate layer 20 is formed to cover at least the magnetization switching region 13. The magnetization switching region 13 and the second free layer 30 are magnetically coupled to each other through the intermediate layer 20.

Claims

1. A magnetic random access memory comprising:

a pinned layer whose magnetization orientation is fixed; and

a magnetic recording layer connected to said pinned layer through a first nonmagnetic layer,

wherein said magnetic recording layer comprises;

a first free layer;

a second free layer being in contact with said first nonmagnetic layer and having reversible magnetization; and

a second nonmagnetic layer provided between said first free layer and said second free layer,

wherein said first free layer includes;

a magnetization switching region having reversible magnetization and overlapping said second free layer;

a first magnetization fixed region connected to a first boundary of said magnetization switching region and whose magnetization orientation is fixed in a first direction; and

a second magnetization fixed region connected to a second boundary of said magnetization switching region and whose magnetization orientation is fixed in a second direction,

wherein both of said first direction and said second direction are directions toward said magnetization switching region or directions away from said magnetization switching region,

said second nonmagnetic layer is so formed as to cover at least said magnetization switching region, and

said magnetization switching region of said first free layer and said second free layer are magnetically coupled to each other through said second nonmagnetic layer.

2. The magnetic random access memory according to claim 1,

wherein said second nonmagnetic layer is so formed as to entirely cover said first free layer.

3. The magnetic random access memory according to claim 1,

wherein said second nonmagnetic layer has a same planar shape as that of said first free layer.

4. The magnetic random access memory according to claim 1,

wherein said magnetization switching region and said second free layer are anti-ferromagnetically coupled to each other through said second nonmagnetic layer.

5. The magnetic random access memory according to claim 1,

wherein said magnetization switching region and said second free layer are ferromagnetically coupled to each other through said second nonmagnetic layer.

6. The magnetic random access memory according to claim 1,

wherein said magnetization switching region and said second free layer are magneto-statically coupled to each other through said second nonmagnetic layer.

7. The magnetic random access memory according to claim 1,

wherein said magnetization switching region, said first magnetization fixed region and said second magnetization fixed region are formed in a same plane.

8. The magnetic random access memory according to claim 1,

wherein magnetization of said magnetization switching region is directed to said first boundary or said second boundary,

a domain wall is formed at said first boundary or said second boundary in said first free layer, and

data writing is performed by moving said domain wall.

9. The magnetic random access memory according to claim 1,

wherein in a first write operation, a first write current is flowed from said first magnetization fixed region to said second magnetization fixed region through said magnetization switching region and a domain wall moves from said second boundary to said first boundary in said magnetization switching region, and

wherein in a second write operation, a second write current is flowed from said second magnetization fixed region to said first magnetization fixed region through said magnetization switching region and a domain wall moves from said first boundary to said second boundary in said magnetization switching region.

10. (canceled)