Memory cells and methods of forming memory cells
View Patent ↗Some embodiments include a memory cell that contains programmable material sandwiched between first and second electrodes. The memory cell can further include a heating element which is directly against one of the electrodes and directly against the programmable material. The heating element can have a thickness in a range of from about 2 nanometers to about 30 nanometers, and can be more electrically resistive than the electrodes. Some embodiments include methods of forming memory cells that include heating elements directly between electrodes and programmable materials.
1. A device comprising:
a structure over a titanium-nitride-containing surface of an electrode, the structure comprising a region including titanium, nitrogen and oxygen, a ratio of nitrogen to oxygen within the region being configured as a gradient of decreasing nitrogen concentration with the highest nitrogen concentration being proximate the electrode; and
programmable material over the structure.
2. The device of claim 1 wherein the programmable material comprises Ge 2 Sb 2 Te 5 .
3. The device of claim 1 wherein the programmable material comprises phase change material.
4. The device of claim 1 wherein the programmable material comprises a chalcogenide.
5. The device of claim 1 wherein the structure has a thickness in a range of from about 2 nanometers to about 30 nanometers.
6. The device of claim 1 wherein the region is a first region, and further comprising a second region consisting of TiO 2 between the programmable material and the first region.
7. The device of claim 1 wherein the programmable material is switchable between two different resistive states.
8. A device comprising:
a structure over a metal-nitride-containing surface of an electrode; the structure comprising first and second portions containing combinations which include all three of metal, nitrogen and oxygen; the first portion being proximate the electrode, the second portion being over the first portion, a ratio of nitrogen to oxygen within the first portion being larger than that within the second portion; and
a programmable material over the structure.
9. The device of claim 8 wherein the programmable material comprises Ge 2 Sb 2 Te 5 .
10. The device of claim 8 wherein the programmable material comprises phase change material.
11. The device of claim 8 wherein the programmable material comprises a chalcogenide.
12. The device of claim 8 wherein the structure has a thickness in a range of from about 2 nanometers to about 30 nanometers.
13. The device of claim 8 wherein the first portion has a stoichiometry approaching TiN.
14. The device of claim 13 wherein the second portion has a stoichiometry approaching TiO 2 .
15. A device comprising:
a structure over a metal-nitride-containing surface of an electrode, the structure comprising a layer including metal, nitrogen and oxygen, where the metal is in common with metal of the electrode; the layer comprising first and second portions, the second portion being over the first portion, a concentration of oxygen within the first portion being less than a concentration of oxygen within the second portion; and
a programmable material over the structure.
16. The device of claim 15 wherein the metal is “M”, where the first portion comprises MO x N y , where x is in a range of from greater than 0 to about 2, and where y is in a range of from greater than or equal to 0 to about 1.
17. The device of claim 16 wherein the first portion has a stoichiometry approaching MN.
18. The device of claim 16 wherein the second portion has a stoichiometry approaching MO 2 .
19. The device of claim 15 wherein the metal is titanium.