Methods of forming memory cells and arrays
Some embodiments include methods of forming memory cells. Heater structures are formed over an array of electrical nodes, and phase change material is formed across the heater structures. The phase change material is patterned into a plurality of confined structures, with the confined structures being in one-to-one correspondence with the heater structures and being spaced from one another by one or more insulative materials that entirely laterally surround each of the confined structures. Some embodiments include memory arrays having heater structures over an array of electrical nodes. Confined phase change material structures are over the heater structures and in one-to-one correspondence with the heater structures. The confined phase change material structures are spaced from one another by one or more insulative materials that entirely laterally surround each of the confined phase change material structures.
1. A method of forming memory cells, comprising:
forming a plurality of heater structures over an array of electrical nodes; the array of electrical nodes having rows extending along a first direction and having columns extending along a second direction substantially orthogonal to the first direction; wordlines being under the array of electrical nodes and extending along the first direction;
forming a phase change material across the plurality of heater structures;
patterning the phase change material into a plurality of confined structures; the plurality of confined structures being spaced from one another by one or more insulative materials that entirely laterally surround each of the confined structures in the plurality of confined structures;
forming bitlines across the plurality of confined structures, with the bitlines extending along the second direction; and
wherein the plurality of heater structures are patterned from lines of heater material that extend along the first direction, and wherein the patterning of the phase change material into the plurality of confined structures comprises:
forming first trenches through the phase change material, with the first trenches extending along the first direction;
lining the first trenches with a first insulative material of the one or more insulative materials;
after forming and lining the first trenches, forming second trenches through the phase change material and the lines of heater material, with the second trenches extending along the second direction and patterning the lines of heater material into the plurality of heater structures; and
lining the second trenches with a second insulative material of the one or more insulative materials.
2. The method of claim 1 wherein the first and second insulative materials are non-oxygen-containing materials.
3. The method of claim 2 wherein the first and second non-oxygen-containing insulative materials have a same composition as one another.
4. The method of claim 2 wherein the first and second non-oxygen-containing insulative materials have different compositions relative to one another.
5. A method of forming memory cells, comprising:
forming lines of heater material over an array of electrical nodes; the array of electrical nodes having rows extending along a first direction and having columns extending along a second direction substantially orthogonal to the first direction; wordlines being under the array of electrical nodes and extending along the first direction; the lines of heater material extending along the first direction and being along rows of the array of electrical nodes;
forming a chalcogenide over the lines of heater material and across the array of electrical nodes;
forming first trenches through the chalcogenide, with the first trenches extending along the first direction;
lining the first trenches with a first insulative material;
after forming and lining the first trenches, forming a patterned bitline material over the chalcogenide; the patterned bitline material forming bitline material lines extending along the second direction;
using the patterned bitline material as a mask during formation of second trenches through the chalcogenide and the lines of heater material, with the second trenches extending along the second direction and patterning the lines of heater material into heater structures while patterning the chalcogenide into confined structures; and
lining the second trenches with a second insulative material.
6. The method of claim 5 wherein the first and second insulative materials comprise silicon nitride.
7. The method of claim 5 wherein a cap of an electrically conductive material is formed over the chalcogenide, and is patterned into blocks over the chalcogenide as the chalcogenide is patterned into the confined structures.
8. The method of claim 7 wherein the cap of the electrically conductive material comprises one or more of Ti, TiN, W, C, Ta and TaN; where the chemical formulas indicate primary components rather than specific stoichiometries.