Ferromagnetic free layer, laminated strucure comprising the same, magnetic tunnel junction structure, magnetoresistive random access memory, and iron-cobalt based target

Patent metadata

Field	Value
Publication number	US-2023397503-A1
Application number	US-202217874593-A
Country	US
Kind code	A1
Filing date	Jul 27, 2022
Priority date	Jun 7, 2022
Publication date	Dec 7, 2023
Grant date	—

Abstract

Provided is a ferromagnetic free layer, comprising Fe, Co, B and an additive metal, and based on a total atomic number of the ferromagnetic free layer, a content of Co is more than 0 at % and less than 30 at %, a content of B is more than 10 at % and less than or equal to 35 at %, and a content of the additive metal is more than or equal to 2 at % and less than 10 at %; the additive metal comprises Mo, Re or a combination thereof, and a thickness of the ferromagnetic free layer is more than or equal to 1.5 nm and less than 2.5 nm. The ferromagnetic free layer can be applied to a MTJ structure as a single layer, and has sufficient thermal stability for maintaining good magnetic properties after thermal treatment, which makes sure that the MTJ structure can exert normal recording function.

First claim

What is claimed is:

1 . A ferromagnetic free layer, comprising, Fe, Co, B and an additive metal, and based on a total atomic number of the ferromagnetic free layer, a content of Co is more than 0 at % and less than 30 at %, a content of B is more than 10 at % and less than or equal to 35 at %, and a content of the additive metal is more than or equal to 2 at % and less than 10 at %;
wherein, the additive metal comprises Mo, Re or a combination thereof, and a thickness of the ferromagnetic free layer is more than or equal to 1.5 nm and less than 2.5 nm.

2 . The ferromagnetic free layer as claimed in claim 1 , wherein based on the total atomic number of the ferromagnetic free layer, the content of B is more than 10 at % and less than 27 at %.

3 . A laminated structure, comprising a ferromagnetic free layer and a tunneling barrier layer, and the ferromagnetic free layer disposed on a surface of the tunneling barrier layer;
wherein, the ferromagnetic free layer is the ferromagnetic free layer as claimed in claim 1 , and a material of the tunneling barrier layer comprises MgO or MgO based materials.

4 . The laminated structure as claimed in claim 3 , wherein an anisotropic field of the laminated structure is more than or equal to 4 kOe.

5 . The laminated structure as claimed in claim 3 , wherein a result of multiplying a magnetocrystalline anisotropy constant of the laminated structure and a thickness of the ferromagnetic free layer is more than or equal to 0.3 erg/cm 2 .

6 . The laminated structure as claimed in claim 4 , wherein a result of multiplying a magnetocrystalline anisotropy constant of the laminated structure and a thickness of the ferromagnetic free layer is more than or equal to 0.3 erg/cm 2 .

7 . A magnetic tunnel junction structure, comprising a ferromagnetic reference layer, a tunneling barrier layer and a ferromagnetic free layer, and the tunneling barrier layer disposed between the ferromagnetic reference layer and the ferromagnetic free layer;
wherein, the ferromagnetic free layer is the ferromagnetic free layer as claimed in claim 1 .

8 . The magnetic tunnel junction structure as claimed in claim 7 , wherein a material of the tunneling barrier layer comprises MgO or MgO based materials.

9 . The magnetic tunnel junction structure as claimed in claim 7 , wherein a material of the ferromagnetic reference layer is selected from the group consisting of: Co, Ni, Fe, CoFe, CoPt, CoPd, CoNi, FePt, FePd, FeB, CoFeB and any combinations thereof.

10 . A magnetoresistive random access memory, comprising a bottom electrode, a pinning layer, a ferromagnetic reference layer, a tunneling barrier layer, a ferromagnetic free layer, and a top electrode from bottom to top; wherein, the ferromagnetic free layer is the ferromagnetic free layer as claimed in claim 1 .

11 . The magnetoresistive random access memory as claimed in claim 10 , wherein a material of the tunneling barrier layer comprises MgO or MgO based materials.

12 . The magnetoresistive random access memory as claimed in claim 10 , wherein a material of the ferromagnetic reference layer is selected from the group consisting of: Co, Ni, Fe, CoFe, CoPt, CoPd, CoNi, FePt, FePd, FeB, CoFeB and any combinations thereof.

13 . The magnetoresistive random access memory as claimed in claim 10 , wherein the top electrode and the bottom electrode each independently comprise a material selected from the group consisting of: Ta, Ru, TaN, TiN, and any combinations thereof.

14 . A FeCo based target, comprising Fe, Co, B and an additive metal, and based on a total atomic number of the FeCo based target, a content of Co is more than 0 at % and less than 30 at %, a content of B is more than 10 at % and less than or equal to 35 at %, and a content of the additive metal is more than or equal to 2 at % and less than 10 at %;
wherein, the additive metal comprises Mo, Re or a combination thereof; the FeCo based target has an α-type FeCo phase, and a ratio of an intensity of (200) crystal plane of the α-type FeCo phase to an intensity of (110) crystal plane of the α-type FeCo phase is more than 0.9.

15 . The FeCo based target as claimed in claim 14 , wherein based on the total atomic number of the FeCo based target, the content of B is more than at % and less than 27 at %.

Assignees

• Solar Applied Materials Tech Corp
• Univ Nat Tsing Hua

Inventors

• Tang Chih-Wen
• Lai Chih-Huang
• Huang Wei-Chih
• Yang Chun-Liang
• Ou Kuan-Ling

Classifications

• C22C38/10

  containing cobalt · CPC title

• H01F10/3268

  the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn · CPC title

• H01F10/3254

  the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ] · CPC title

• H10N50/85 Primary

  Materials of the active region · CPC title

• H01L43/10 Primary

  Electricity · mapped topic