US2013175646A1PendingUtilityA1

Magnetic structures, methods of forming the same and memory devices including a magnetic structure

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Assignee: KIM KWANG-SEOKPriority: Jan 6, 2012Filed: Jul 16, 2012Published: Jul 11, 2013
Est. expiryJan 6, 2032(~5.5 yrs left)· nominal 20-yr term from priority
Inventors:Kwang-Seok KimSung-Chul Lee
G11C 11/161H01F 10/3254H01F 41/302H01F 10/3286H01F 10/30B82Y 40/00G11C 11/15G11C 11/1675H10N 50/01H10N 50/10H10B 61/22H10N 50/80
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Claims

Abstract

Magnetic structures, methods of forming the same, and memory devices including a magnetic structure, include a magnetic layer, and a stress-inducing layer on a first surface of the magnetic layer, a non-magnetic layer on a second surface of the magnetic layer. The stress-inducing layer is configured to induce a compressive stress in the magnetic layer. The magnetic layer has a lattice structure compressively strained due to the stress-inducing layer.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
         1 . A magnetic structure, comprising:
 a magnetic layer;   a stress-inducing layer on a first surface of the magnetic layer; and   a non-magnetic layer on a second surface of the magnetic layer,   wherein the stress-inducing layer is configured to induce a compressive stress in the magnetic layer, and the magnetic layer has a lattice structure compressively strained due to the stress-inducing layer.   
     
     
         2 . The magnetic structure of  claim 1 , wherein the magnetic layer has interface perpendicular magnetic anisotropy (IPMA) due to an interface between the magnetic layer and the non-magnetic layer. 
     
     
         3 . The magnetic structure of  claim 1 , wherein the magnetic layer includes a Fe-based material or a CoFe-based material. 
     
     
         4 . The magnetic structure of  claim 3 , wherein the CoFe-based material includes CoFeB. 
     
     
         5 . The magnetic structure of  claim 1 , wherein the non-magnetic layer includes an oxide. 
     
     
         6 . The magnetic structure of  claim 5 , wherein the oxide includes a magnesium (Mg) oxide. 
     
     
         7 . The magnetic structure of  claim 1 , wherein the stress-inducing layer includes a material with a thermal expansion coefficient higher than a thermal expansion coefficient of the magnetic layer. 
     
     
         8 . The magnetic structure of  claim 7 , wherein the stress-inducing layer includes at least one of Al, Ga, Mn, Zn, Cu and combinations thereof. 
     
     
         9 . The magnetic structure of  claim 1 , wherein the stress-inducing layer include a phase transformation material. 
     
     
         10 . The magnetic structure of  claim 1 , wherein the stress-inducing layer includes a material with a lattice parameter smaller than a lattice parameter of the magnetic layer. 
     
     
         11 . The magnetic structure of  claim 1 , wherein the magnetic layer is between the stress-inducing layer and the non-magnetic layer. 
     
     
         12 . The magnetic structure of  claim 1 , wherein the magnetic layer includes,
 a first layer in contact with the non-magnetic layer; and   a second layer between the first layer and the stress-inducing layer,   wherein a saturation magnetization (Ms) of the second layer is smaller than a saturation magnetization of the first layer.   
     
     
         13 . The magnetic structure of  claim 12 , wherein the magnetic layer has a thickness of about 1 nm to about 3 nm. 
     
     
         14 . The magnetic structure of  claim 1 , wherein the magnetic layer is a first magnetic layer,
 the magnetic structure further comprises a second magnetic layer on a surface of the non-magnetic layer, and   the non-magnetic layer is between the first magnetic layer and the second magnetic layer.   
     
     
         15 . The magnetic structure of  claim 14 , wherein one of the first and second magnetic layers is a free layer, and the other is a pinned layer. 
     
     
         16 . The magnetic structure of  claim 14 , wherein the magnetic structure is a magnetoresistive element. 
     
     
         17 . A method of forming a magnetic structure, the method comprising:
 forming a magnetic layer having a lattice structure compressively strained due to a stress-inducing layer; and   forming a non-magnetic layer contacting the magnetic layer.   
     
     
         18 . The method of  claim 17 , wherein the magnetic layer has interface perpendicular magnetic anisotropy (IPMA) due to an interface between the magnetic layer and the non-magnetic layer. 
     
     
         19 . The method of  claim 17 , wherein the stress-inducing layer is formed of a material with a thermal expansion coefficient higher than a thermal expansion coefficient of the magnetic layer. 
     
     
         20 . The method of  claim 19 , wherein forming the magnetic layer includes,
 heating the stress-inducing layer;   forming a magnetic material layer on the heated stress-inducing layer; and   cooling the magnetic material layer and the stress-inducing layer such that the lattice structure of the magnetic material layer is compressively strained and the magnetic layer is formed.   
     
     
         21 . The method of  claim 19 , wherein forming the magnetic layer includes,
 forming a magnetic material layer;   heating the magnetic material layer;   forming the stress-inducing layer on the heated magnetic material layer; and   cooling the stress-inducing layer and the magnetic material layer such that the lattice structure of the magnetic material layer is compressively strained and the magnetic layer is formed.   
     
     
         22 . The method of  claim 17 , wherein the stress-inducing layer is formed of a phase transformation material. 
     
     
         23 . The method of  claim 22 , wherein forming the magnetic layer includes,
 forming the stress-inducing layer and a magnetic material layer in contact with the stress-inducing layer; and   changing a phase of the stress-inducing layer such that the lattice structure of the magnetic material layer is compressively strained.   
     
     
         24 . The method of  claim 17 , wherein the stress-inducing layer is formed of a material with a lattice parameter smaller than a lattice parameter of the magnetic layer. 
     
     
         25 . The method of  claim 17 , wherein the magnetic layer includes,
 a first layer in contact with the non-magnetic layer; and   a second layer disposed between the first layer and the stress-inducing layer, and   wherein a saturation magnetization (Ms) of the second layer is smaller than a saturation magnetization of the first layer.   
     
     
         26 . The method of  claim 17 , wherein the magnetic layer is a first magnetic layer,
 the method further comprises forming a second magnetic layer on a surface of the non-magnetic layer, and   the non-magnetic layer is disposed between the first and second magnetic layer.   
     
     
         27 . The method of  claim 26 , wherein one of the first and second magnetic layers is a free layer, and the other is a pinned layer. 
     
     
         28 . A memory device, comprising:
 at least one memory cell including a magnetoresistive element, wherein the magnetoresistive element includes,
 first and second magnetic layers spaced apart from each other, 
 a non-magnetic layer between the first and second magnetic layers, and 
 a stress-inducing layer configured to induce a compressive stress in the first magnetic layer, wherein the first magnetic layer has a lattice structure compressively strained due to the stress-inducing layer. 
   
     
     
         29 . The memory device of  claim 28 , wherein the memory cell further includes a switching element connected to the magnetoresistive element. 
     
     
         30 . The memory device of  claim 28 , wherein the first magnetic layer is a free layer, and the second magnetic layer is a pinned layer. 
     
     
         31 . The memory device of  claim 28 , wherein the first magnetic layer has interface perpendicular magnetic anisotropy (IPMA) due to an interface between the first magnetic layer and the non-magnetic layer. 
     
     
         32 . The memory device of  claim 28 , wherein the stress-inducing layer includes a material with a thermal expansion coefficient higher than a thermal expansion coefficient of the first magnetic layer. 
     
     
         33 . The memory device of  claim 28 , wherein the stress-inducing layer includes a phase transformation material. 
     
     
         34 . The memory device of  claim 28 , wherein the stress-inducing layer includes a material with a lattice parameter smaller than a lattice parameter of the first magnetic layer. 
     
     
         35 . The memory device of  claim 28 , wherein the first magnetic layer includes,
 a first layer in contact with the non-magnetic layer; and   a second layer disposed between the first layer and the stress-inducing layer,   wherein a saturation magnetization (Ms) of the second layer is smaller than a saturation magnetization of the first layer.   
     
     
         36 . The memory device of  claim 28 , wherein the memory device is a spin transfer torque magnetic random access memory (STT-MRAM).

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