Magnetic memory element with composite perpendicular enhancement layer

• US 9,780,300 B2
• Filed: 11/30/2016
• Issued: 10/03/2017
• Est. Priority Date: 02/16/2011
• Status: Active Grant

• Current Assignee: Avalanche Technology Incorporated
• Original Assignee: Avalanche Technology Incorporated
• Inventors: Zhou, Yuchen, Yen, Bing K., Gan, Huadong, Huai, Yiming
• Primary Examiner(s): ARMAND, MARC ANTHONY
• Application Number:
  US15/365,371
• Publication Number:
  US 20170084826A1
• Time in Patent Office: 307 Days
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: H01F 10/3286 Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy
• CPC Class Codes: H01F 10/329 Spin-exchange coupled multilayers wherein the magnetisation of the free layer is switched by a spin-polarised current, e.g. spin torque effect
• CPC Class Codes: H01F 41/302 for applying spin-exchange-coupled multilayers, e.g. nanostructured superlattices spin-exchange-coupled multilayers H01F10/32
• CPC Class Codes: H01L 29/66984 Devices using spin polarized carriers
• CPC Class Codes: H10B 61/22 of the field-effect transistor [FET] type
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 50/80 Constructional details
• CPC Class Codes: H10N 50/85 Magnetic active materials

Abstract

The present invention is directed to an MTJ memory element comprising a magnetic free layer structure including one or more magnetic free layers that have a variable magnetization direction substantially perpendicular to layer planes thereof; an insulating tunnel junction layer formed adjacent to the magnetic free layer structure; a magnetic reference layer structure including a first magnetic reference layer and a second magnetic reference layer with a perpendicular enhancement layer interposed therebetween, the first and second magnetic reference layers having a first fixed magnetization direction substantially perpendicular to layer planes thereof; an anti-ferromagnetic coupling layer formed adjacent to the second magnetic reference layer; and a magnetic fixed layer formed adjacent to the anti-ferromagnetic coupling layer. The non-magnetic perpendicular enhancement layer includes a first perpendicular enhancement sublayer formed adjacent to the first magnetic reference layer and a second perpendicular enhancement sublayer formed adjacent to the second magnetic reference layer.

Claims

1. A magnetic tunnel junction (MTJ) memory element comprising:

a magnetic free layer structure including one or more magnetic free layers that have a variable magnetization direction substantially perpendicular to layer planes thereof;

an insulating tunnel junction layer formed adjacent to said magnetic free layer structure;

a magnetic reference layer structure including one or more magnetic reference layers that have a first fixed magnetization direction substantially perpendicular to layer planes thereof;

an anti-ferromagnetic coupling layer formed adjacent to said magnetic reference layer structure opposite said insulating tunnel junction layer;

a magnetic fixed layer formed adjacent to said anti-ferromagnetic coupling layer opposite said magnetic reference layer structure, said magnetic fixed layer having a second fixed magnetization direction that is substantially perpendicular to a layer plane thereof and is substantially opposite to said first fixed magnetization direction; and

an iridium seed layer formed adjacent to said magnetic fixed layer opposite said anti-ferromagnetic coupling layer.

2. The MTJ memory element of claim 1, wherein said magnetic reference layer structure includes a first magnetic reference layer formed adjacent to said insulating tunnel junction layer and a second magnetic reference layer separated from said first magnetic reference layer by a perpendicular enhancement layer, said first and second magnetic reference layers having said first fixed magnetization direction substantially perpendicular to layer planes thereof.

3. The MTJ memory element of claim 1, wherein said magnetic free layer structure includes a first magnetic free layer formed adjacent to said insulating tunnel junction layer and a second magnetic free layer separated from said first magnetic free layer by a perpendicular enhancement layer, said first and second magnetic free layers having said variable magnetization direction substantially perpendicular to layer planes thereof.

4. A magnetic tunnel junction (MTJ) memory element comprising:

a magnetic free layer structure including one or more magnetic free layers that have a variable magnetization direction substantially perpendicular to layer planes thereof;

an insulating tunnel junction layer formed adjacent to said magnetic free layer structure;

a magnetic reference layer structure including a first magnetic reference layer formed adjacent to said insulating tunnel junction layer and a second magnetic reference layer separated from said first magnetic reference layer by a non-magnetic perpendicular enhancement layer, said first and second magnetic reference layers having a first fixed magnetization direction substantially perpendicular to layer planes thereof;

an anti-ferromagnetic coupling layer formed adjacent to said second magnetic reference layer opposite said non-magnetic perpendicular enhancement layer; and

a magnetic fixed layer formed adjacent to said anti-ferromagnetic coupling layer opposite said second magnetic reference layer, said magnetic fixed layer having a second fixed magnetization direction that is substantially perpendicular to a layer plane thereof and is substantially opposite to said first fixed magnetization direction,

wherein said non-magnetic perpendicular enhancement layer includes a first perpendicular enhancement sublayer formed adjacent to said first magnetic reference layer and a second perpendicular enhancement sublayer formed adjacent to said second magnetic reference layer.

5. The MTJ memory element of claim 4, wherein said first magnetic reference layer is made of an alloy comprising cobalt, iron, and boron.

6. The MTJ memory element of claim 4, wherein said first perpendicular enhancement sublayer is made of tungsten or molybdenum.

7. The MTJ memory element of claim 4, wherein said second perpendicular enhancement sublayer is made of tantalum or hafnium.

8. The MTJ memory element of claim 4, wherein said second perpendicular enhancement sublayer is made of zirconium or niobium.

9. The MTJ memory element of claim 4, wherein said non-magnetic perpendicular enhancement layer further includes a third perpendicular enhancement sublayer formed between said first and second perpendicular enhancement sublayers.

10. The MTJ memory element of claim 9, wherein said first and second perpendicular enhancement sublayers are made of molybdenum or tungsten, said third perpendicular enhancement sublayer is made of tantalum or hafnium.

11. A magnetic tunnel junction (MTJ) memory element comprising:

a magnetic free layer structure including one or more magnetic free layers that have a variable magnetization direction substantially perpendicular to layer planes thereof;

an insulating tunnel junction layer formed adjacent to said magnetic free layer structure;

a magnetic reference layer structure including one or more magnetic reference layers that have a first fixed magnetization direction substantially perpendicular to layer planes thereof;

an anti-ferromagnetic coupling layer formed adjacent to said magnetic reference layer structure opposite said insulating tunnel junction layer;

a magnetic fixed layer formed adjacent to said anti-ferromagnetic coupling layer opposite said magnetic reference layer structure, said magnetic fixed layer having a second fixed magnetization direction that is substantially perpendicular to a layer plane thereof and is substantially opposite to said first fixed magnetization direction;

a first non-magnetic layer formed adjacent to said magnetic free layer structure opposite said insulating tunnel junction layer; and

a second non-magnetic layer formed adjacent to said first non-magnetic layer opposite said magnetic free layer structure.

12. The MTJ memory element of claim 11, wherein said magnetic free layer structure includes a magnetic free layer made of an alloy comprising cobalt, iron, and boron.

13. The MTJ memory element of claim 11, wherein said first non-magnetic layer is made of tungsten or molybdenum.

14. The MTJ memory element of claim 11, wherein said second non-magnetic layer is made of tantalum or hafnium.

15. The MTJ memory element of claim 11, wherein said second non-magnetic layer is made of zirconium or niobium.

16. A magnetic tunnel junction (MTJ) memory element comprising:

a magnetic free layer structure including a first magnetic free layer and a second magnetic free layer with a non-magnetic perpendicular enhancement layer interposed therebetween, said first and second magnetic free layers having a variable magnetization direction substantially perpendicular to layer planes thereof;

an insulating tunnel junction layer formed adjacent to said first magnetic free layer;

a magnetic reference layer structure including one or more magnetic reference layers that have a first fixed magnetization direction substantially perpendicular to layer planes thereof;

an anti-ferromagnetic coupling layer formed adjacent to said magnetic reference layer structure opposite said insulating tunnel junction layer; and

a magnetic fixed layer formed adjacent to said anti-ferromagnetic coupling layer opposite said magnetic reference layer structure, said magnetic fixed layer having a second fixed magnetization direction that is substantially perpendicular to a layer plane thereof and is substantially opposite to said first fixed magnetization direction,

wherein said non-magnetic perpendicular enhancement layer includes a first perpendicular enhancement sublayer formed adjacent to said first magnetic free layer and a second perpendicular enhancement sublayer formed adjacent to said second magnetic free layer.

17. The MTJ memory element of claim 16, wherein said first magnetic free layer is made of an alloy comprising cobalt, iron, and boron.

18. The MTJ memory element of claim 16, wherein said first perpendicular enhancement sublayer is made of tungsten or molybdenum.

19. The MTJ memory element of claim 16, wherein said second perpendicular enhancement sublayer is made of tantalum or hafnium.

20. The MTJ memory element of claim 16, wherein said second perpendicular enhancement sublayer is made of zirconium or niobium.

21. The MTJ memory element of claim 16, wherein said non-magnetic perpendicular enhancement layer further includes a third perpendicular enhancement sublayer formed between said first and second perpendicular enhancement sublayers.

22. The MTJ memory element of claim 21, wherein said first and second perpendicular enhancement sublayers are made of molybdenum or tungsten, said third perpendicular enhancement sublayer is made of tantalum or hafnium.