Memory device and memory system
Provided is a memory device that has a structure suitable for still higher integration while securing production easiness, and includes n memory cell units stacked, on a substrate, in order as first to n-th memory cell units in a first direction. The n memory cell units each include: one or more first electrodes; a plurality of second electrodes each provided to intersect the first electrode; a plurality of memory cells provided at respective intersections of the first electrode and the second electrodes and each coupled to both the first and second electrodes; and one or more lead lines coupled to the first electrode to form one or more coupling parts, which, in (m+1)-th memory cell unit, are located at a position where the coupling parts and m-th memory cell region surrounded by the memory cells in m-th memory cell unit overlap each other in the first direction.
1. A memory device comprising
n-number of memory cell units that are provided on a substrate and stacked in order as a first memory cell unit to an n-th memory cell unit in a first direction,
the n-number of memory cell units each including
one or more first electrodes,
a plurality of second electrodes each provided to intersect the first electrode,
a plurality of memory cells provided at respective intersections of the first electrode and the plurality of second electrodes, and each coupled to both of the first electrode and a corresponding one of the second electrodes, and
one or more lead lines that are coupled to the first electrode to form one or more coupling parts,
the one or more coupling parts in an (m+1)-th memory cell unit of the memory cell units being located at a position where the one or more coupling parts and an m-th memory cell region overlap each other in the first direction, where m denotes a natural number equal to or smaller than n, the m-th memory cell region being surrounded by the plurality of memory cells in an m-th memory cell unit of the memory cell units, wherein the one or more coupling parts in the (m+1)-th memory cell unit are located at a position where the one or more coupling parts and the plurality of memory cells in the m-th memory cell unit overlap each other in the first direction.
2. The memory device according to claim 1 , wherein an (m+1)-th memory cell region surrounded by the plurality of memory cells in the (m+1)-th memory cell unit is narrower than the m-th memory cell region.
3. The memory device according to claim 1 , wherein the number of the plurality of memory cells in the (m+1)-th memory cell unit is smaller than the number of the plurality of memory cells in the m-th memory cell unit.
4. The memory device according to claim 1 , wherein
the plurality of memory cells each include a resistance change element including a stacked structure of an ion supply layer and an insulating layer, and
the resistance change element is interposed between the first electrode and the second electrode.
5. The memory device according to claim 1 , further comprising a drive circuit coupled to the lead line.
6. The memory device according to claim 1 , wherein
the first electrode comprises a plate-shaped electrode that extends along a first surface that is orthogonal to the first direction,
the plurality of second electrodes comprise a plurality of columnar electrodes that each stand from the plate-shaped electrode toward the substrate, and
the plate-shaped electrode in the (m+1)-th memory cell unit has an occupation area that is smaller than an occupation area of the plate-shaped electrode in the m-th memory cell unit.
7. The memory device according to claim 6 , further comprising a plurality of selection lines that are arranged in a second direction along the first surface, and extend in a third direction orthogonal to the second direction along the first surface, the plurality of selection lines being each coupled to the plurality of second electrodes that are arranged in the third direction.
8. The memory device according to claim 1 , wherein
the first electrode comprises a plurality of first linear electrodes and a plurality of second linear electrodes that each extend in a second direction along a first surface that is orthogonal to the first direction, and are arranged alternately in a third direction along the first surface,
the plurality of second electrodes comprise a plurality of columnar electrodes each interposed between the first linear electrode and the second linear electrode that are adjacent to each other,
the plurality of memory cells comprise a plurality of storage layers each interposed between corresponding one of the plurality of the columnar electrodes and corresponding one of each of the plurality of first linear electrodes and the plurality of second linear electrodes, the first linear electrodes and the second linear electrodes facing each other to interpose the columnar electrodes, and
the lead line comprises a first contact pillar that forms a first coupling part as the coupling part through coupling to the first linear electrode, and a second contact pillar that forms a second coupling part as the coupling part through coupling to the second linear electrode.
9. The memory device according to claim 8 , wherein
the first linear electrode in the (m+1)-th memory cell unit has a size, in the second direction, that is smaller than a size, in the second direction, of the first linear electrode in the m-th memory cell unit, and
the second linear electrode in the (m+1)-th memory cell unit has a size, in the second direction, that is smaller than a size, in the second direction, of the second linear electrode in the m-th memory cell unit.
10. The memory device according to claim 8 , wherein
a plurality of the first contact pillars coupled to the respective first linear electrodes in the m-th memory cell unit are coupled in common to one of first beams, and
a plurality of the second contact pillars coupled to the respective second linear electrodes in the m-th memory cell unit are coupled in common to one of second beams.
11. The memory device according to claim 1 , wherein
the plurality of second electrodes, the plurality of memory cells, and the plurality of first electrodes are stacked in order from side of the substrate in the first direction,
the plurality of memory cells each have a stacked structure in which a resistance change element and a selection element are stacked in order on corresponding one of the plurality of second electrodes, and
the resistance change element has a planar shape that is substantially same as one of the plurality of first electrodes.
12. The memory device according to claim 11 , wherein
the plurality of first electrodes are disposed to each extend in a second direction along the first surface and to be arranged in a third direction orthogonal to the second direction,
the plurality of second electrodes are disposed to each extend in the third direction and to be arranged in the second direction,
a plurality of the selection elements are disposed to be arranged in both of the second direction and the third direction, and
the single resistance change element is coupled in common to the plurality of the selection elements that are arranged in one of the second direction and the third direction.
13. The memory device according to claim 11 , wherein
an (m+1)-th memory cell region surrounded by the plurality of memory cells in the (m+1)-th memory cell unit is narrower than the m-th memory cell region, and
the lead line comprises a first contact pillar and a second contact pillar, the first contact pillar forming a first coupling part as the coupling part through coupling to the first electrode and extending to be away from the substrate, the second contact pillar forming a second coupling part as the coupling part through coupling to the second electrode and extending to be away from the substrate.
14. The memory device according to claim 13 , further comprising:
a drive circuit provided between the substrate and a first memory cell unit of the memory cell units;
a first wiring line that couples an upper end of the first contact pillar and the drive circuit to each other; and
a second wiring line that couples an upper end of the second contact pillar and the drive circuit to each other.
15. The memory device according to claim 11 , wherein the lead line comprises a first contact pillar and a second contact pillar, the first contact pillar forming a first coupling part as the coupling part through coupling to the first electrode and extending to be away from the substrate, the second contact pillar forming a second coupling part as the coupling part through coupling to the second electrode and extending toward the substrate.
16. The memory device according to claim 15 , further comprising:
a drive circuit provided between the substrate and a first memory cell unit of the memory cell units;
a first wiring line that couples an upper end of the first contact pillar and the drive circuit to each other; and
a second wiring line that couples a lower end of the second contact pillar and the drive circuit to each other.
17. A memory system comprising:
a memory device; and
a controller that controls the memory device,
the memory device being provided with n-number of memory cell units that are provided on a substrate and stacked in order as a first memory cell unit to an n-th memory cell unit in a first direction, the n-number of memory cell units each including
one or more first electrodes,
a plurality of second electrodes each provided to intersect the first electrode,
a plurality of memory cells provided at respective intersections of the first electrode and the plurality of second electrodes, the plurality of memory cells each coupled to both of the first electrode and a corresponding one of the second electrodes, and
one or more lead lines that are coupled to the first electrode to form one or more coupling parts, the one or more coupling parts in an (m+1)-th memory cell unit of the memory cell units being located at a position where the one or more coupling parts and an m-th memory cell region overlap each other in the first direction, the m-th memory cell region being surrounded by the plurality of memory cells in an m-th memory cell unit of the memory cell units, where m denotes a natural number equal to or smaller than n, wherein the one or more coupling parts in the (m+1)-th memory cell unit are located at a position where the one or more coupling parts and the plurality of memory cells in the m-th memory cell unit overlap each other in the first direction.
18. The memory system according to claim 17 , wherein the memory cell provided in a peripheral region, of the m-th memory cell region, serves as a spare memory cell, the peripheral region being a region other than a region that is overlapped, in the first direction, by an (m+1)-th memory cell region surrounded by the plurality of memory cells in the (m+1)-th memory cell unit.