Memory cells, memory arrays, and 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 a memory array, comprising:
forming heater structures over an array of electrical nodes; the heater structures being in one-to-one correspondence with the 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;
forming confined phase change material structures over the heater structures and in one-to-one correspondence with the heater structures, having lateral peripheries of a phase change material, the array having x-direction axes extending through the confined phase change material structures along the first direction and y-direction axes extending through the confined phase change material structures along the second direction;
forming bitlines across the confined phase change material structures, with the bitlines extending along the second direction;
forming conductive material caps between and contacting the bitlines and the confined phase change material structures, the confined phase change material structures and conductive material caps being spaced from one another along the x-direction axes by first insulative material regions comprising a first oxide-containing material having a first pair of opposing vertical sidewalls sandwiched between first nitride-containing materials that extend vertically along an entirety of the first pair of opposing vertical sidewalls, the confined phase change material structures and conductive material caps further being spaced from one another along the y-direction axes by second insulative material regions comprising a second oxide-containing material having a second pair of opposing vertically extending sidewalls sandwiched between second nitride-containing materials that extend vertically along an entirety of the second pair of opposing vertically extending sidewalls; and
the lateral peripheries of the confined phase change material structures, the conductive material caps and the heater structures being entirely laterally surrounded by the first and second nitride-containing materials.
2. The method of claim 1 wherein the first and second nitride-containing materials are silicon nitride.
3. The method of claim 1 wherein the second insulative material regions are less deep than the first insulative material regions.
4. The method of claim 1 wherein the heater structures are configured as angled plates.
5. The method of claim 1 wherein the heater structures are configured as solid rods.
6. The method of claim 1 wherein the heater structures are configured as hollow tubes.
7. The method of claim 1 wherein the heater structures are formed over wordlines extending along the first direction.
8. The method of claim 7 wherein the heater structures are coupled to the wordlines by intervening select devices.
9. The method of claim 1 further comprising forming an additional conductive material over the bitlines.
10. The method of claim 9 wherein the additional conductive material is patterned into lines directly over and along the bitlines.
11. The method of claim 9 wherein the additional conductive material comprises at least one of copper and tungsten.