Methods of forming memory cells, arrays of magnetic memory cells, and semiconductor devices
View Patent ↗Magnetic memory cells, methods of fabrication, semiconductor device structures, and memory systems are disclosed. A magnetic cell core includes at least one magnetic region (e.g., a free region or a fixed region) configured to exhibit a vertical magnetic orientation, at least one oxide-based region, which may be a tunnel junction region or an oxide capping region, and at least one magnetic interface region, which may comprise or consist of iron (Fe). In some embodiments, the magnetic interface region is spaced from at least one oxide-based region by a magnetic region. The presence of the magnetic interface region enhances the perpendicular magnetic anisotropy (PMA) strength of the magnetic cell core. In some embodiments, the PMA strength may be enhanced more than 50% compared to that of the same magnetic cell core structure lacking the magnetic interface region.
1. A method of forming a memory cell, the method comprising:
forming a magnetic material over a substrate;
forming an oxide material over the magnetic material;
forming another magnetic material over the oxide material;
forming another oxide material over the another magnetic material;
forming, by magnetron sputtering, an iron-based material, to a thickness of less than about ten angstroms, between the another magnetic material and one of the oxide material and the another oxide material; and
patterning the magnetic material, the oxide material, the another magnetic material, the another oxide material, and the iron-based material to form a magnetic cell core comprising a free region formed from one of the magnetic material and the another magnetic material, a fixed region formed from another of the magnetic material and the another magnetic material, an electrically insulating region disposed between the free region and the fixed region and formed from the oxide material, a magnetic interface region formed from the iron-based material, and an oxide capping region disposed above the free region and the fixed region and formed from the another oxide material, the magnetic material and the another magnetic material exhibiting a vertical magnetic orientation.
2. The method of claim 1 , further comprising annealing the oxide material, the magnetic material, the another oxide material, and the iron-based material.
3. The method of claim 1 , wherein forming an iron-based material comprises forming the iron-based material to contact the oxide material and to exhibit a same crystal orientation as exhibited by the oxide material.
4. The method of claim 1 , wherein forming an iron-based material comprises forming a material consisting of iron.
5. The method of claim 1 , wherein forming an iron-based material, to a thickness of less than about ten angstroms, comprises forming a monolayer of the iron-based material.
6. The method of claim 1 , wherein forming an iron-based material between the another magnetic material and one of the oxide material and the another oxide material comprises forming the iron-based material directly between the another magnetic material and the oxide material.
7. The method of claim 1 , wherein forming an iron-based material between the another magnetic material and one of the oxide material and the another oxide material comprises forming the iron-based material directly between the another magnetic material and the another oxide material.
8. The method of claim 1 , further comprising forming another iron-based material spaced from the iron-based material by at least a portion of one of the magnetic material and the another magnetic material.
9. A method of forming an array of magnetic memory cells, the method comprising:
forming a material structure, comprising:
forming a magnetic material over a substrate, the magnetic material exhibiting a switchable magnetic orientation;
forming another magnetic material over the substrate, the another magnetic material exhibiting a fixed magnetic orientation;
forming a nonmagnetic material vertically between the magnetic material and the another magnetic material;
forming an oxide-based nonmagnetic material separated from the nonmagnetic material by the magnetic material; and
forming a monolayer of an iron-based material in contact with one of the magnetic material and the another magnetic material;
patterning the material structure to form at least one cell core of a magnetic memory cell of the array.
10. The method of claim 9 , wherein forming a magnetic material, forming another magnetic material, and forming a nonmagnetic material comprise:
forming the another magnetic material before forming the magnetic material and before forming the nonmagnetic material;
forming the nonmagnetic material above the another magnetic material; and
forming the magnetic material above the nonmagnetic material.
11. The method of claim 9 , wherein forming the material structure further comprises forming another monolayer of an iron-based material in contact with the one of the magnetic material and the another magnetic material, the monolayer of the iron-based material spaced from the another monolayer of the iron-based material.
12. The method of claim 9 , wherein forming the material structure further comprises forming another monolayer of an iron-based material in contact with another of the magnetic material and the another magnetic material.
13. The method of claim 9 , wherein forming a monolayer of an iron-based material comprises forming the monolayer of the iron-based material internal to the one of the magnetic material and the another magnetic material.
14. The method of claim 9 , wherein forming a monolayer of an iron-based material comprises forming a monolayer of cobalt-iron (CoFe).
15. A method of forming a semiconductor device comprising at least one STT-MRAM cell, the method comprising:
forming a material structure, comprising:
forming a magnetic material over a nonmagnetic oxide material, the magnetic material exhibiting a switchable magnetic orientation;
forming another nonmagnetic oxide material over the magnetic material;
forming another magnetic material spaced from the magnetic material by one of the nonmagnetic oxide material and the another nonmagnetic oxide material, the another magnetic material exhibiting a fixed magnetic orientation; and
forming, by magnetron sputtering, an iron-based material between the nonmagnetic oxide material and the another nonmagnetic oxide material, the iron-based material defining a thickness of less than about ten angstroms; and
patterning the material structure to form at least one cell core of the at least one STT-MRAM cell.
16. The method of claim 15 , wherein forming the material structure further comprises forming another iron-based material defining a thickness of less than about ten angstroms, the iron-based material spaced from the another iron-based material.
17. The method of claim 16 , wherein:
forming an iron-based material comprises forming the iron-based material directly adjacent a surface of the one of the nonmagnetic oxide material and the another nonmagnetic oxide material; and
forming another iron-based material comprises forming the another iron-based material directly adjacent another surface of the one of the nonmagnetic oxide material and the another nonmagnetic oxide material.
18. The method of claim 15 , wherein forming an iron-based material between the nonmagnetic oxide material and the another nonmagnetic oxide material comprises forming the iron-based material between sub-regions of the magnetic material.
19. The method of claim 18 , wherein forming the iron-based material between sub-regions of the magnetic material comprises forming the iron-based material directly adjacent a spacer material between the sub-regions of the magnetic material.
20. The method of claim 15 :
wherein forming another magnetic material precedes forming the magnetic material and forming the another nonmagnetic oxide material; and
further comprising, before forming the magnetic material, forming the nonmagnetic oxide material over the another magnetic material.