Memory device and method of manufacturing the same

1. A memory device comprising:

a first electrode line layer including a plurality of first electrode lines extending on a substrate in a first direction and being spaced apart from each other;

a second electrode line layer including a plurality of second electrode lines formed on the first electrode line layer and extending in a second direction that is different from the first direction and being spaced apart from each other;

a memory cell layer including a plurality of first memory cells located at intersections of the plurality of first electrode lines and the plurality of second electrode lines, each first memory cell including a lower electrode, a selection device, an intermediate electrode and a variable resistance layer that are sequentially stacked; and;

an integrated circuit layer disposed under the first electrode line layer and formed on the substrate, the integrated circuit layer including peripheral circuits for driving the first memory cells,

wherein the variable resistance layer becomes gradually wider or narrower toward an upper portion of the variable resistance layer,

wherein a width of each of the first memory cells gradually decreases from the lower electrode toward an upper portion of the plurality of first memory cells, and

wherein an interlayer insulating layer is disposed between the first electrode line layer and the integrated circuit layer, and an interconnection structure is disposed to electrically connect the first memory cells to the peripheral circuits through the interlayer insulating layer.

2. The memory device of claim 1 ,

wherein each of the first memory cells comprises a spacer surrounding a side surface of the variable resistance layer, and

wherein an outer side surface of the spacer constitutes a portion of a side surface slope of the plurality of first memory cells.

3. The memory device of claim 2 , wherein the spacer has a width that gradually increases toward its upper portion.

4. The memory device of claim 2 , wherein an outer side surface of the spacer is aligned with side surfaces of the selection device and the intermediate electrode.

5. The memory device of claim 2 , wherein a minimum combined width of the variable resistance layer and the spacer is less than a maximum width of the selection device.

6. The memory device of claim 1 , wherein a distance between two adjacent ones of the first memory cells in an upper portion of the first memory cells is different from a distance between the two adjacent ones in a lower portion of the first memory cells.

7. The memory device of claim 6 , wherein a width of the variable resistance layer corresponding to the upper portion is less than a width of the selection device corresponding to the lower portion.

8. The memory device of claim 1 , further comprising:

a first insulating layer extending in the first direction and disposed between the plurality of first electrode lines; and

a second insulating layer disposed on the first insulating layer and the first electrode lines, and disposed between the plurality of first memory cells,

wherein the first insulating layer has a recess formed in an upper portion of the first insulating layer.

9. The memory device of claim 8 , the second insulating layer extends between the plurality of first electrode lines toward its lower portion, and a lower surface of the second insulating layer is lower than upper surfaces of the plurality of first electrode lines.

10. The memory device of claim 1 , wherein the variable resistance layer comprises at least one of GeSbTe, InSbTe and BiSbTe, or has a superlattice structure including GeTe layers and SbTe layers that are alternately and repeatedly stacked.

11. The memory device of claim 1 , wherein the selection device is formed in at least one of an ovonic threshold switching (OTS) device, a diode and a transistor.

12. The memory device of claim 1 , wherein the selection device is formed in an ovonic threshold switching (OTS) device, and the OTS device comprise at least two of silicon (Si), germanium (Ge), antimony (Sb), telleryum (Te), selenium (Se), indium (In) and tin (Sn) on a basis of arsenic (As) or comprises at least two of silicon (Si), germanium (Ge), antimony (Sb), telleryum (Te), arsenic (As), indium (In) and tin (Sn) on a basis of selenium (Se).

13. The memory device of claim 1 , further comprising:

a third electrode line layer disposed over the second electrode line layer, the third electrode line layer including a plurality of third electrode lines extending in the first direction and being spaced apart from each other; and

a second memory cell layer including a plurality of second memory cells located at intersections of the plurality of second electrode lines and the plurality of third electrode lines, each second memory cell including a lower electrode, a selection device, an intermediate electrode and a variable resistance layer that are sequentially stacked.

14. The memory device of claim 13 , further comprising:

a first top electrode line layer disposed over the third electrode line layer, the first top electrode line layer including a plurality of first top electrode lines extending in the first direction and being spaced apart from each other;

a second top electrode line layer disposed over the first top electrode line layer, the second top electrode line layer including a plurality of second top electrode lines extending in the second direction and being spaced apart from each other;

a third top electrode line layer disposed over the second top electrode line layer, the third top electrode line layer including a plurality of third top electrode lines extending in the first direction and being spaced apart from each other;

a first top memory cell layer including a plurality of first top memory cells located at intersections of the plurality of first top electrode lines and the plurality of second top electrode lines, each first top memory cell including a lower electrode, a selection device, an intermediate electrode and a variable resistance layer that are sequentially stacked; and

a second top memory cell layer including a plurality of second top memory cells located at intersections of the plurality of second top electrode lines and the plurality of third top electrode lines, each second top memory cell including a lower electrode, a selection device, an intermediate electrode and a variable resistance layer that are sequentially stacked.

15. The memory device of claim 1 , wherein the integrated circuit layer includes a plurality of transistors on the substrate, a multilevel interconnection structures connected to the plurality of transistors, and a plurality of interlayer insulating layers insulating the multilevel interconnection structures from each other.

16. A memory device comprising:

a first electrode line layer including a plurality of first electrode lines extending on a substrate in a first direction and being spaced apart from each other;

a second electrode line layer including a plurality of second electrode lines formed on the first electrode line layer and extending in a second direction that is different from the first direction and being spaced apart from each other;

a memory cell layer including a plurality of first memory cells located at intersections of the plurality of first electrode lines and the plurality of second electrode lines, each first memory cell including a lower electrode, a selection device, an intermediate electrode and a variable resistance layer that are sequentially stacked; and

an integrated circuit layer disposed under the first electrode line layer and formed on the substrate,

wherein the variable resistance layer becomes gradually wider or narrower toward an upper portion of the variable resistance layer,

wherein a width of the variable resistance layer is less than a width of the selection device, and a distance between two adjacent ones of the first memory cells in a portion corresponding to the variable resistance layer is different from a distance between the two adjacent ones in a portion corresponding to the selection device, and

wherein an interlayer insulating layer is disposed between the first electrode line layer and the integrated circuit layer, and an interconnection structure is disposed to electrically connect the first memory cells to peripheral circuits of the integrated circuit layer through the interlayer insulating layer.

17. The memory device of claim 16 , further comprising:

a first insulating layer extending in the first direction and disposed between the plurality of first electrode lines; and

a second insulating layer disposed on the first insulating layer and the first electrode lines, and disposed between the plurality of first memory cells,

wherein the first insulating layer has a recess formed in an upper portion of the first insulating layer.

18. The memory device of claim 17 ,

wherein each of the first memory cells comprises a spacer surrounding a side surface of the variable resistance layer,

wherein an outer side surface of the spacer constitutes a portion of a side surface slope of the plurality of first memory cells, and

wherein a minimum combined width of the variable resistance layer and the spacer is less than a maximum width of the selection device.

19. A memory device comprising:

a first electrode line layer including a plurality of first electrode lines extending on a substrate in a first direction and being spaced apart from each other;

a second electrode line layer including a plurality of second electrode lines formed on the first electrode line layer and extending in a second direction that is different from the first direction and being spaced apart from each other;

a memory cell layer including a plurality of first memory cells located at intersections of the plurality of first electrode lines and the plurality of second electrode lines, each first memory cell including a lower electrode, a selection device, an intermediate electrode and a variable resistance layer that are sequentially stacked;

an integrated circuit layer disposed under the first electrode line layer and formed on the substrate;

a first insulating layer extending in the first direction and disposed between the plurality of first electrode lines; and

a second insulating layer disposed on the first insulating layer and the first electrode lines, and disposed between the plurality of first memory cells,

wherein the variable resistance layer becomes gradually wider or narrower toward an upper portion of the variable resistance layer, and

wherein the first insulating layer has a recess formed in an upper portion of the first insulating layer.

20. The memory device of claim 19 ,

wherein each of the first memory cells comprises a spacer surrounding a side surface of the variable resistance layer,

wherein an outer side surface of the spacer constitutes a portion of a side surface slope of the plurality of first memory cells, and

wherein a minimum combined width of the variable resistance layer and the spacer is less than a maximum width of the selection device.