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 memory cell, comprising:
a multi-layer structure across a titanium-nitride-containing surface of an electrode; the multi-layer structure having a thickness in a range of from about 2 nanometers to about 30 nanometers; one of the layers of the multi-layer structure being a first layer and being directly against the first electrode; the first layer comprising TiO 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; a ratio of nitrogen to oxygen within the TiO x N y being configured as a gradient of decreasing nitrogen concentration with the highest nitrogen concentration being directly against the first electrode; another of the layers of the multi-layer structure being a second layer and consisting of TiO 2 ; and
programmable material over the second layer.
2. The memory cell of claim 1 wherein the programmable material comprises Ge 2 Sb 2 Te 5 .
3. The memory cell of claim 1 wherein the programmable material comprises phase change material.
4. The memory cell of claim 1 wherein the programmable material comprises a chalcogenide.
5. A memory cell, comprising:
an oxygen-containing structure across a titanium-nitride-containing surface of an electrode; the structure having a thickness in a range of from about 2 nanometers to about 30 nanometers, and comprising a first region directly against the first electrode; the first region comprising TiO 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; a ratio of nitrogen to oxygen within the TiO x N y being configured as a gradient of decreasing nitrogen concentration with the highest nitrogen concentration being directly against the first electrode; the structure comprising a second region over the first region, with the second region consisting of TiO 2 ; and
programmable material over the second region.
6. The memory cell of claim 5 wherein the programmable material comprises Ge 2 Sb 2 Te 5 .
7. The memory cell of claim 5 wherein the programmable material comprises phase change material.
8. The memory cell of claim 5 wherein the programmable material comprises a chalcogenide.
9. A memory cell, comprising:
a metal-nitride-containing first electrode;
an oxygen-containing structure along a surface of the first electrode; the structure having a thickness in a range of from about 2 nanometers to about 30 nanometers, and comprising a first region directly against the first electrode surface; the first region comprising 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, and where M is a metal in common with metal of the first electrode; a ratio of nitrogen to oxygen within the MO x N y being configured as a gradient of decreasing nitrogen concentration with the highest nitrogen concentration being directly against the first electrode; the structure comprising a second region over the first region, with the second region consisting of MO 2 ;
a chalcogenide-containing programmable material directly against the second region; and
a second electrode adjacent an opposing side of the programmable material relative to the first electrode.
10. The memory cell of claim 9 wherein M is titanium.