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. A semiconductor device, comprising:
a magnetic structure comprising:
a fixed region exhibiting a fixed vertical magnetic orientation; and
a free region exhibiting a switchable vertical magnetic orientation, wherein the free region comprises an alternating structure of magnetic sub-regions and coupler sub-regions, wherein each of the coupler sub-regions is configured to effect anti-parallel coupling in at least one neighboring magnetic sub-region, 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.
2. The semiconductor device of claim 1 , wherein the coupler sub-regions are configured to antiferromagnetically couple neighboring magnetic sub-regions.
3. The semiconductor device of claim 1 , wherein at least one magnetic sub-region of the plurality of magnetic sub-regions is located between to other magnetic sub-regions, the two other magnetic sub-regions having a magnetic orientation oppositely directed relative to the at least one magnetic sub-region.
4. The semiconductor device of claim 1 , wherein the magnetic sub-regions comprise cobalt, iron, nickel, and alloys thereof.
5. The semiconductor device of claim 1 , wherein the magnetic sub-regions comprise CoNiFeX, wherein X comprises one of B, Cu, Re, Ru, Rh, Hf, Pd, Pt, or C.
6. The semiconductor device of claim 1 , wherein the coupler sub-regions comprise one or more of ruthenium and rhodium.
7. The semiconductor device of claim 1 , wherein the coupler sub-regions comprise a monolayer of coupler material.
8. The semiconductor device of claim 1 , wherein an uppermost sub-region and a lowermost sub-region of the free region each comprise a magnetic sub-region.
9. The semiconductor device of claim 1 , wherein the fixed region comprises another alternating structure of magnetic sub-regions and coupler sub-regions.
10. The semiconductor device of claim 1 , wherein the fixed region comprises a lower region and a upper region separated by a coupler material, wherein the lower region and the upper region each comprise alternating regions of magnetic material and conductive material.
11. A system, comprising:
a processor;
a semiconductor device operably coupled to the processor, the semiconductor device including a magnetic structure comprising:
a fixed region having a fixed vertical magnetic orientation; and
a free region having a free vertical magnetic orientation,
at least one of the fixed region or the free region comprising an alternating structure of magnetic sub-regions and coupler sub-regions, wherein each magnetic sub-region of the magnetic sub-regions exhibits an oppositely directed vertical magnetic orientation than a nearest magnetic sub-region,
the magnetic structure configured to emit a stronger magnetic dipole field near sidewalls of the fixed region.
12. The system of claim 11 , wherein each of the coupler sub-regions effects anti-parallel coupling in at least one neighboring magnetic sub-structure.
13. The system of claim 11 , wherein each of the magnetic sub-regions and the coupler sub-regions has a thickness of less than about one nanometer.
14. The system of claim 11 , further comprising a reference region between the fixed region and the free region, the reference region comprising a magnetic material.
15. A semiconductor device, comprising:
a magnetic structure comprising:
a fixed region exhibiting a fixed vertical magnetic orientation, the fixed region comprising a first alternating structure of magnetic sub-regions and coupler sub-regions, more than one of the magnetic sub-regions of the first alternating structure of the fixed region located between two other magnetic sub-regions of the first alternating structure and having an oppositely directed magnetic orientation relative to a magnetic orientation of the two other magnetic sub-regions; and
a free region exhibiting a switchable vertical magnetic orientation, wherein the free region comprises a second alternating structure of magnetic sub-regions and coupler sub-regions.
16. The semiconductor device of claim 15 , wherein each of the coupler sub-regions of at least one of the fixed region or the free region is configured to effect anti-parallel coupling in at least one neighboring magnetic sub-region.
17. The semiconductor device of claim 15 , wherein the magnetic sub-regions of at least one of the fixed region or the free region have a thickness less than about 4 Angstroms.
18. The semiconductor device of claim 15 , wherein the coupler sub-regions of at least one of the fixed region or the free region have a thickness less than about 6 Angstroms.
19. The semiconductor device of claim 15 , wherein the magnetic sub-regions of the second alternating structure exhibit oppositely directed vertical magnetic orientations.