Magnetic structures, semiconductor structures, and semiconductor devices
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.
1. An apparatus, comprising:
a fixed region exhibiting a fixed vertical magnetic orientation; and
a free region exhibiting a switchable vertical magnetic orientation, the free region comprising an alternating structure of magnetic sub-regions and coupler sub-regions, at least one of the magnetic sub-regions having an oppositely directed magnetic orientation as a magnetic orientation of two of the nearest magnetic sub-regions, wherein a magnetic dipole field emitted by the at least one of the magnetic sub-regions is configured to be substantially canceled by an oppositely directed magnetic dipole field emitted from one or two neighboring magnetic sub-regions of the one of the magnetic sub-regions.
2. The apparatus of claim 1 , wherein the magnetic sub-regions comprise cobalt, nickel, iron, or alloys thereof.
3. The apparatus of claim 1 , wherein the coupler sub-regions comprise one or both of ruthenium and rhodium.
4. The apparatus of claim 1 , wherein each of the magnetic sub-regions and the coupler sub-regions individually comprise a monolayer.
5. The apparatus of claim 1 , wherein each of the magnetic sub-regions and the coupler sub-regions individually comprise from about one monolayer to about five monolayers.
6. The apparatus of claim 1 , wherein the fixed region comprises another alternating structure of magnetic sub-regions and coupler sub-regions.
7. The apparatus of claim 6 , wherein the free region comprises fewer alternating magnetic sub-regions and coupler sub-regions than the fixed region.
8. The apparatus of claim 1 , wherein the free region comprises one more coupler sub-region than a number of magnetic sub-regions.
9. A cell core structure, comprising:
a fixed region exhibiting a fixed vertical magnetic orientation;
a transitional region comprising a non-magnetic material adjacent to the fixed region; and
a free region exhibiting a switchable vertical magnetic orientation adjacent to the transitional region, one or both of the fixed region and the free region comprising an alternating structure of magnetic sub-regions and coupler sub-regions, more than one of the magnetic sub-regions located between two other magnetic sub-regions and having an oppositely directed magnetic orientation relative to a magnetic orientation of the two other magnetic sub-regions.
10. The cell core structure of claim 9 , wherein the transitional region comprises tantalum, titanium, nitrides thereof, or combinations thereof.
11. The cell core structure of claim 9 , further comprising a non-magnetic material adjacent to the transitional region and between the free region and the fixed region.
12. The cell core structure of claim 9 , wherein an uppermost sub-region of the alternating structure comprises a coupler sub-region and a lowermost sub-region of the alternating structure comprises a coupler sub-region.
13. The cell core structure of claim 9 , wherein the free region is configured to emit a stronger magnetic dipole field near sidewalls thereof.
14. A system, comprising:
a processor; and
a magnetic structure comprising a magnetic cell core coupled to the processor, the magnetic cell core comprising:
a fixed region comprising a first alternating structure of magnetic sub-regions and coupler sub-regions, each magnetic sub-region spaced from another magnetic sub-region by one of the coupler sub-regions and having an oppositely directed magnetic orientation as neighboring magnetic sub-regions, each coupler sub-region of the fixed region configured to effect anti-parallel coupling in at least one adjacent magnetic sub-structure of the fixed region;
a non-magnetic region adjacent to the fixed region; and
a free region adjacent to the non-magnetic region, the free region comprising a second alternating structure of magnetic sub-regions and coupler sub-regions, each magnetic sub-region spaced from another magnetic sub-region by one of the coupler sub-regions and having an oppositely directed magnetic orientation as neighboring magnetic sub-regions.
15. The system of claim 14 , further comprising a reference region comprising a magnetic material between the fixed region and the free region.
16. The system of claim 15 , wherein the reference region comprises a third alternating structure of magnetic sub-regions and coupler sub-regions.
17. The system of claim 16 , wherein the reference region comprises fewer magnetic sub-regions and coupler sub-regions than the free region.
18. An apparatus, comprising:
a fixed region exhibiting a fixed vertical magnetic orientation; and
a free region exhibiting a switchable vertical magnetic orientation, the free region comprising an alternating structure of magnetic sub-regions and coupler sub-regions, at least one of the magnetic sub-regions having an oppositely directed magnetic orientation as a magnetic orientation of two of the nearest magnetic sub-regions, each of the magnetic sub-regions and the coupler sub-regions individually comprising from about one monolayer to about five monolayers.