Memory arrays with polygonal memory cells having specific sidewall orientations
Some embodiments include a memory array having a first series of access/sense lines which extend along a first direction, a second series of access/sense lines over the first series of access/sense lines and which extend along a second direction substantially orthogonal to the first direction, and memory cells vertically between the first and second series of access/sense lines. Each memory cell is uniquely addressed by a combination of an access/sense line from the first series and an access/sense line from the second series. The memory cells have programmable material. At least some of the programmable material within each memory cell is a polygonal structure having a sidewall that extends along a third direction which is different from the first and second directions. Some embodiments include methods of forming memory arrays.
1. A memory array, comprising:
a first series of access/sense lines extending along a first lateral direction relative to an upper surface of a substrate;
a second series of access/sense lines elevationally, over the first series of access/sense lines and extending along a second lateral direction which is substantially orthogonal to the first lateral direction; and
memory cells extending vertically upward relative to the upper surface and being disposed between the first and second series of access/sense lines; each memory cell being uniquely addressed by a combination of an access/sense line from the first series and an access/sense line from the second series; the memory cells comprising programmable material; at least some of the programmable material within each memory cell being a polygonal structure having a sidewall that extends along a third lateral direction which is different from the first and second lateral directions.
2. The memory array of claim 1 wherein the polygonal structure is substantially a parallelepiped.
3. The memory array of claim 2 wherein the sidewall is one of a pair of substantially identical longest sidewalls of the parallelepiped.
4. The memory array of claim 1 wherein the programmable material comprises phase change material.
5. The memory array of claim 1 wherein the programmable material comprises chalcogenide.
6. The memory array of claim 1 wherein all of the programmable material within each memory cell is configured as said polygonal structure.
7. The memory array of claim comprising select devices between the memory cells and the first access/sense lines; the select devices having sidewalls extending along the third lateral direction.
8. The memory array of claim 1 wherein the polygonal structure is a second polygonal structure, wherein only some of the programmable material within each memory cell is configured as said second polygonal structure, and wherein some of the programmable material within each memory cell is configured as a first polygonal structure beneath said second polygonal structure and having a different shape than the second polygonal structure.
9. The memory array of claim 8 wherein a portion of the programmable material configured as the first polygonal structure is a first portion of the programmable material of the memory cell; wherein a portion of the programmable material configured as the second polygonal structure is a second portion of the programmable material of the memory cell; and wherein each memory cell further comprises a separating material between the first and second portions.
10. The memory array of claim 9 further comprising select devices between the memory cells and the first access/sense lines; the select devices having sidewalls parallel to sidewalls of the first polygonal structures.
11. The memory array of claim 9 wherein the first and second portions are a same composition as one another.
12. The memory array of claim 9 wherein the first and second portions are different compositions relative to one another.
13. The memory array of claim 9 wherein the separating material comprises carbon.
14. The memory array of claim 8 wherein a portion of the programmable material configured as the first polygonal structure is a first portion of the programmable material of the memory cell; wherein a portion of the programmable material configured as the second polygonal structure is a second portion of the programmable material of a memory cell; and wherein the second portion is a different composition from the first portion.
15. The memory array of claim 14 wherein the first and second portions comprise chalcogenide.