Magnetic random access memory structures, integrated circuits, and methods for fabricating the same

• US 10,446,205 B1
• Filed: 03/28/2018
• Issued: 10/15/2019
• Est. Priority Date: 03/28/2018
• Status: Active Grant

• Current Assignee: Globalfoundries Singapore Pte Limited (GlobalFoundries, Inc.)
• Original Assignee: Globalfoundries Singapore Pte Limited (GlobalFoundries, Inc.)
• Inventors: Tahmasebi, Taiebeh, Houssameddine, Dimitri, Tran, Michael Nicolas Albert, Wang, Chenchen Jacob
• Primary Examiner(s): Hoang, Huan
• Application Number:
  US15/938,770
• Publication Number:
  US 20190304522A1
• Time in Patent Office: Days
• Field of Search: 365158, 365171, 365173
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• 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 11/1655 Bit-line or column circuits
• CPC Class Codes: G11C 11/1657 Word-line or row circuits
• CPC Class Codes: G11C 11/1659 Cell access
• CPC Class Codes: H10B 61/22 of the field-effect transistor [FET] type
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• 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

Spin transfer torque magnetic random access memory structures, integrated circuits, and methods for fabricating integrated circuits are provided. An exemplary spin transfer torque magnetic random access memory structure has a perpendicular magnetic orientation, and includes a bottom electrode, a seed layer over the bottom electrode, a hard layer over the seed layer, a magnetically continuous transition layer over the hard layer, a reference layer over the magnetically continuous transition layer, a tunnel barrier layer over the reference layer, a storage layer formed over the tunnel barrier layer, and a top electrode. The reference layer, the tunnel barrier layer, and the storage layer form a magnetic tunnel junction (MTJ) element with a perpendicular orientation.

Claims

1. A spin transfer torque magnetic random access memory structure having a perpendicular magnetic orientation, comprising:

a bottom electrode;

a seed layer over the bottom electrode;

a hard layer over the seed layer;

a magnetically continuous transition layer over the hard layer;

a reference layer over the magnetically continuous transition layer;

a tunnel barrier layer over the reference layer;

a storage layer formed over the tunnel barrier layer, wherein the reference layer, the tunnel barrier layer, and the storage layer form a magnetic tunnel junction (MTJ) element with a perpendicular orientation; and

a top electrode.

2. The spin transfer torque magnetic random access memory structure of claim 1 wherein the magnetically continuous transition layer is an alloy of iron (Fe), cobalt (Co), nickel (Ni), boron (B), or combinations thereof.

3. The spin transfer torque magnetic random access memory structure of claim 1 wherein the magnetically continuous transition layer includes a magnetic sublayer and a non-magnetic sublayer.

4. The spin transfer torque magnetic random access memory structure of claim 1 wherein the magnetically continuous transition layer includes a magnetic sublayer selected from iron (Fe), cobalt (Co), nickel (Ni), cobalt iron boride (CoFeB), iron boron (FeB) or combination of thereof, and a non-magnetic sublayer selected from molybdenum (Mo), tungsten (W), niobium (Nb), vanadium (V), zirconium (Zr), chromium (Cr), tantalum (Ta), titanium (Ti) or combination of thereof.

5. The spin transfer torque magnetic random access memory structure of claim 1 wherein the magnetically continuous transition layer includes a magnetic sublayer of cobalt iron boron (CoFeB) and a non-magnetic sublayer of molybdenum or tungsten.

6. The spin transfer torque magnetic random access memory structure of claim 1 wherein the magnetically continuous transition layer includes a magnetic sublayer of cobalt iron boron (CoFeB) and a non-magnetic sublayer of molybdenum or tungsten, and wherein the magnetically continuous transition layer has a non-magnetic concentration of at least about 10%.

7. The spin transfer torque magnetic random access memory structure of claim 1 wherein the magnetically continuous transition layer includes a magnetic sublayer of cobalt iron boron (CoFeB) and a non-magnetic sublayer of molybdenum, and wherein the magnetically continuous transition layer has a molybdenum concentration of about 40% to about 60%.

8. The spin transfer torque magnetic random access memory structure of claim 1 wherein the magnetically continuous transition layer includes a magnetic sublayer of cobalt iron boron (CoFeB) and a non-magnetic sublayer of tungsten, and wherein the magnetically continuous transition layer has a tungsten concentration of about 40% to about 60%.

9. The spin transfer torque magnetic random access memory structure of claim 1 wherein the magnetically continuous transition layer has a thickness of from about 4 A to about 10 A.

10. The spin transfer torque magnetic random access memory structure of claim 1 wherein the magnetically continuous transition layer has a thickness of about 8 A.

11. The spin transfer torque magnetic random access memory structure of claim 1 wherein the hard layer includes an anti-parallel layer, wherein the magnetically continuous transition layer is disposed on the anti-parallel layer, and wherein the anti-parallel layer is a single magnetic layer or a magnetic bilayer.

12. The spin transfer torque magnetic random access memory structure of claim 1 wherein the reference layer is disposed directly on the magnetically continuous transition layer.

13. The spin transfer torque magnetic random access memory structure of claim 1 wherein the hard layer includes an anti-parallel layer, wherein the magnetically continuous transition layer is disposed on the anti-parallel layer, and wherein the anti-parallel layer is a cobalt/platinum (Co/Pt) bilayer, a cobalt/nickel (Co/Ni) bilayer, an iron platinum (FePt) alloy, or a cobalt platinum (CoPt) alloy.

14. A spin transfer torque magnetic random access memory structure having a perpendicular magnetic orientation, comprising:

a bottom electrode;

a seed layer over the bottom electrode;

an anti-parallel layer over the seed layer;

a non-magnetic synthetic anti-ferromagnetic (SAF) coupling layer over the anti-parallel layer;

a magnetic hard layer disposed on the non-magnetic SAF coupling layer, wherein the magnetic hard layer has a thickness of from about 6 A to about 35 A;

a tunnel barrier layer over the magnetic hard layer;

a storage layer formed over the tunnel barrier layer, wherein the magnetic hard layer, the tunnel barrier layer, and the storage layer form a magnetic tunnel junction (MTJ) element with a perpendicular orientation; and

a top electrode.

15. The spin transfer torque magnetic random access memory structure of claim 14 wherein the tunnel barrier layer is disposed on the magnetic hard layer, and wherein the storage layer is disposed on the tunnel barrier layer.

16. The spin transfer torque magnetic random access memory structure of claim 14 wherein the synthetic anti-ferromagnetic non-magnetic SAF coupling layer is ruthenium or iridium.

17. The spin transfer torque magnetic random access memory structure of claim 14 wherein the magnetic hard layer is a single magnetic layer or a composite structure of magnetic and non-magnetic sublayers.

18. The spin transfer torque magnetic random access memory structure of claim 14 wherein the magnetic hard layer is a single magnetic layer or a composite structure of magnetic and non-magnetic sublayers, wherein the magnetic layer or sublayer is selected from iron (Fe), cobalt (Co), nickel (Ni), cobalt iron boride (CoFeB), iron boron (FeB) or combination of thereof, and wherein the non-magnetic sublayer is selected from molybdenum (Mo), tungsten (W), niobium (Nb), vanadium (V), zirconium (Zr), chromium (Cr), tantalum (Ta), titanium (Ti) or combination of thereof.

19. A method for fabricating an integrated circuit, the method comprising:

forming a bottom electrode;

forming a seed layer over the bottom electrode;

forming an anti-parallel layer over the seed layer;

forming a non-magnetic synthetic anti-ferromagnetic (SAF) coupling layer over the magnetic SAF layer;

forming a magnetic layer directly on the SAF coupling layer, wherein;

the magnetic layer is a magnetically continuous transition layer, wherein the magnetically continuous transition layer is an alloy or wherein the magnetically continuous transition layer includes a magnetic sublayer and a non-magnetic sublayer;

or

the magnetic layer is a magnetic hard layer, wherein the magnetic hard layer is a single magnetic layer or a composite structure of magnetic and non-magnetic sublayers;

forming a tunnel barrier layer over the magnetic layer;

forming a storage layer over the tunnel barrier layer; and

forming a top electrode over the storage layer.

20. The method of claim 19 wherein:

the magnetically continuous transition layer is an alloy of iron (Fe), cobalt (Co), nickel (Ni), boron (B), or combinations thereof, or wherein the magnetically continuous transition layer includes a magnetic sublayer selected from iron (Fe), cobalt (Co), nickel (Ni), cobalt iron boride (CoFeB), iron boron (FeB) or combination of thereof, and a non-magnetic sublayer selected from molybdenum (Mo), tungsten (W), niobium (Nb), vanadium (V), zirconium (Zr), chromium (Cr), tantalum (Ta), titanium (Ti) or combination of thereof;

or

wherein the magnetic hard layer is a single magnetic layer or a composite structure of magnetic and non-magnetic sublayers, wherein the magnetic layer or sublayer is selected from iron (Fe), cobalt (Co), nickel (Ni), cobalt iron boride (CoFeB), iron boron (FeB) or combination of thereof, and wherein the non-magnetic sublayer is selected from molybdenum (Mo), tungsten (W), niobium (Nb), vanadium (V), zirconium (Zr), chromium (Cr), tantalum (Ta), titanium (Ti) or combination of thereof.