Magnetic memory cells and semiconductor devices comprising the magnetic memory cells

Patent metadata

Field	Value
Publication number	US-2017309680-A1
Application number	US-201715642577-A
Country	US
Kind code	A1
Filing date	Jul 6, 2017
Priority date	Jun 19, 2012
Publication date	Oct 26, 2017
Grant date	—

Abstract

Memory cells are disclosed. Magnetic regions within the memory cells include an alternating structure of magnetic sub-regions and coupler sub-regions. The coupler material of the coupler sub-regions antiferromagnetically couples neighboring magnetic sub-regions and effects or encourages a vertical magnetic orientation exhibited by the neighboring magnetic sub-regions. Neighboring magnetic sub-regions, spaced from one another by a coupler sub-region, exhibit oppositely directed magnetic orientations. The magnetic and coupler sub-regions may each be of a thickness tailored to form the magnetic region in a compact structure. Interference between magnetic dipole fields emitted from the magnetic region on switching of a free region in the memory cell may be reduced or eliminated. Also disclosed are semiconductor device structures, spin torque transfer magnetic random access memory (STT-MRAM) systems, and methods of fabrication.

First claim

What is claimed is:

1 . A magnetic memory cell comprising:
a magnetic cell core comprising:
magnetic regions, the magnetic regions comprising:
a free region exhibiting a switchable vertical magnetic orientation; and
a fixed region exhibiting a fixed vertical magnetic orientation, the free region having a horizontal surface defining a smaller surface area than a surface area defined by a horizontal surface of the fixed region,
at least one of the magnetic regions comprising an alternating structure of magnetic sub-regions and coupler sub-regions, the magnetic sub-regions each defining a height less than a height defined by each of the coupler sub-regions; and

a non-magnetic region between the free region and the fixed region.

2 . The magnetic memory cell of claim 1 , wherein each coupler sub-region of the coupler sub-regions is antiferromagnetically coupled to at least one neighboring magnetic sub-region of the magnetic sub-regions.

3 . The magnetic memory cell of claim 1 , wherein each of the coupler sub-regions is directly between two magnetic sub-regions.

4 . The magnetic memory cell of claim 1 , wherein each of the coupler sub-regions effects anti-parallel coupling in at least one neighboring magnetic sub-region.

5 . The magnetic memory cell of claim 1 , wherein the magnetic sub-regions of the alternating structure exhibit oppositely directed vertical magnetic orientations.

6 . The magnetic memory cell of claim 1 , wherein the fixed region comprises the alternating structure of the magnetic sub-regions and the coupler sub-regions.

7 . The magnetic memory cell of claim 1 , wherein each of the free region and the fixed region comprises the alternating structure of the magnetic sub-regions and the coupler sub-regions.

8 . A magnetic memory cell comprising:
a magnetic cell core comprising:
magnetic regions, the magnetic regions comprising:
a free region exhibiting a switchable vertical magnetic orientation; and
a fixed region exhibiting a fixed vertical magnetic orientation,
at least one of the magnetic regions comprising an alternating structure of magnetic sub-regions and coupler sub-regions, the magnetic sub-regions each defining a height less than a height defined by each of the coupler sub-regions; and

a non-magnetic region between the free region and the fixed region, the non-magnetic region being electrically insulative.

9 . The magnetic memory cell of claim 8 , wherein a lateral dimension of the free region is smaller than a lateral dimension of the fixed region.

10 . The magnetic memory cell of claim 8 , wherein the magnetic cell core is configured to emit a stronger magnetic dipole field near sidewalls of the fixed region.

11 . The magnetic memory cell of claim 8 , wherein the free region and the fixed region comprise alternating structures of magnetic sub-regions and coupler sub-regions and the number of magnetic sub-regions in the free region is less than the number of magnetic sub-regions in the fixed region.

12 . The magnetic memory cell of claim 8 , wherein each of the coupler sub-regions comprises ruthenium (Ru), rhodium (Rh), or combinations thereof.

13 . The magnetic memory cell of claim 8 , wherein the fixed region is free of palladium, platinum, or combinations thereof.

14 . The magnetic memory cell of claim 8 , wherein each of the magnetic sub-regions and the coupler sub-regions has a thickness of less than about one nanometer.

15 . The magnetic memory cell of claim 8 , wherein the fixed region comprises a superlattice structure of the magnetic sub-regions and the coupler sub-regions.

16 . The magnetic memory cell of claim 8 , wherein the non-magnetic region comprises a magnetic tunnel junction.

17 . The magnetic memory cell of claim 8 , wherein the non-magnetic region comprises a spin valve.

18 . The magnetic memory cell of claim 8 , wherein each of the magnetic sub-regions consists of cobalt.

19 . A semiconductor device, comprising:
an array of magnetic memory cells, at least one magnetic memory cell of the array comprising:
at least one magnetic region comprising an alternating structure of magnetic sub-regions and coupler sub-regions thicker than the magnetic sub-regions, magnetic material of the at least one magnetic region exhibiting a vertical magnetic orientation, neighboring magnetic sub-regions of the alternating structure being antiferromagnetically coupled with one another, and each of the magnetic sub-regions consisting of a monolayer of the magnetic material.

20 . The semiconductor device of claim 19 , wherein the alternating structure of magnetic sub-regions and coupler sub-regions comprises the magnetic sub-regions spaced apart from one another by the coupler sub-regions.

Assignees

• Micron Technology Inc

Inventors

• Kinney Wayne I
• Kula Witold
• Kramer Stephen J

Classifications

• H01F10/3218 Primary

  Exchange coupling of magnetic films via an antiferromagnetic interface (H01F10/3268 takes precedence) · CPC title

• H01F10/329

  Spin-exchange coupled multilayers wherein the magnetisation of the free layer is switched by a spin-polarised current, e.g. spin torque effect · CPC title

• G11C11/1675

  Writing or programming circuits or methods · CPC title

• G11C11/1673

  Reading or sensing circuits or methods · CPC title

• G11C11/161

  details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell · CPC title