Memory cell with resistance-switching layers and lateral arrangement
View Patent ↗A memory device in a 3-D read and write memory includes memory cells. Each memory cell includes a resistance-switching memory element (RSME). The RSME has first and second resistance-switching layers on either side of a conductive intermediate layer, and first and second electrodes at either end of the RSME. The layers can be provided in a lateral arrangement, such as an end-to-end, face-to-face, L-shaped or U-shaped arrangement. In a set or reset operation of the memory cell, an electric field is applied across the first and second electrodes. An ionic current flows in the resistance-switching layers, contributing to a switching mechanism. An electron flow, which does not contribute to the switching mechanism, is reduced due to scattering by the conductive intermediate layer, to avoid damage to the steering element.
1. A resistance-switching memory cell, comprising:
first and second electrodes;
a conductive or semiconductive intermediate layer electrically between, and in series with, the first and second electrodes;
a first resistance-switching layer electrically between, and in series with, the first electrode and the conductive or semiconductive intermediate layer; and
a second resistance-switching layer electrically between, and in series with, the second electrode and the conductive or semiconductive intermediate layer, at least one of the first electrode, the second electrode, the conductive or semiconductive intermediate layer, the first resistance-switching layer, and the second resistance-switching layer is arranged laterally, at least in part, of at least one other of the first electrode, the second electrode, the conductive or semiconductive intermediate layer, the first resistance-switching layer, or the second resistance-switching layer.
2. The resistance-switching memory cell of claim 1 , wherein:
the lateral arrangement is end-to-end.
3. The resistance-switching memory cell of claim 1 , wherein:
at least one of: (a) the first resistance-switching layer is arranged laterally, end-to-end, with the first electrode, or (b) the second resistance-switching layer is arranged laterally, end-to-end, with the second electrode.
4. The resistance-switching memory cell of claim 1 , wherein:
the conductive or semiconductive intermediate layer is arranged laterally, end-to-end, with at least one of the first or second resistance-switching layers.
5. The resistance-switching memory cell of claim 1 , wherein:
the lateral arrangement is face-to-face.
6. The resistance-switching memory cell of claim 1 , wherein:
the first resistance-switching layer, the conductive or semiconductive intermediate layer and the second resistance-switching layer are each arranged laterally with one another, face-to-face.
7. The resistance-switching memory cell of claim 1 , wherein:
the first electrode, the first resistance-switching layer, the conductive or semiconductive intermediate layer the second resistance-switching layer and the second electrode are each arranged laterally with one another, face-to-face.
8. The resistance-switching memory cell of claim 1 , wherein:
the conductive or semiconductive intermediate layer and the first and second resistance-switching layers are L-shaped or U-shaped.
9. The resistance-switching memory cell of claim 1 , further comprising:
a diode steering element in series with the first and second electrodes, the conductive or semiconductive intermediate layer, and the first and second resistance-switching layers.
10. A resistance-switching memory cell, comprising:
first and second electrodes;
a conductive or semiconductive intermediate layer electrically between, and in series with, the first and second electrodes
a first resistance-switching layer electrically between, and in series with, the first electrode and the conductive or semiconductive intermediate layer; and
a second resistance-switching layer electrically between, and in series with, the second electrode and the conductive or semiconductive intermediate layer, the conductive or semiconductive intermediate layer and the first and second resistance-switching layers are L-shaped or U-shaped.
11. The resistance-switching memory cell of claim 10 , wherein:
the conductive or semiconductive intermediate layer and the first and second resistance-switching layers are L-shaped.
12. The resistance-switching memory cell of claim 11 , wherein:
the first resistance-switching layer is nested within the conductive or semiconductive intermediate layer, and the conductive or semiconductive intermediate layer is nested within the second resistance-switching layer.
13. The resistance-switching memory cell of claim 12 , wherein:
the second electrode is L-shaped, and the second resistance-switching layer is nested within the second electrode.
14. The resistance-switching memory cell of claim 10 , wherein:
the conductive or semiconductive intermediate layer and the first and second resistance-switching layers are U-shaped.
15. The resistance-switching memory cell of claim 14 , wherein:
the first resistance-switching layer is nested within the conductive or semiconductive intermediate layer, and the conductive or semiconductive intermediate layer is nested within the second resistance-switching layer.
16. The resistance-switching memory cell of claim 15 , wherein:
the second electrode is L-shaped, and the second resistance-switching layer is nested within the second electrode.
17. The resistance-switching memory cell of claim 10 , further comprising:
a diode steering element in series with the first and second electrodes, the conductive or semiconductive intermediate layer, and the first and second resistance-switching layers.
18. A memory device, comprising:
a memory array comprising a plurality of resistance-switching memory cells, each resistance-switching memory cell comprising a steering element in series with a resistance-switching memory element, each resistance-switching memory element comprising an intermediate layer electrically between first and second resistance-switching layers, and first and second electrodes;
for each resistance-switching memory cell: at least one of the first electrode, the second electrode, the conductive or semiconductive intermediate layer, the first resistance-switching layer, or the second resistance-switching layer is arranged laterally, at least in part, of at least one other of the first electrode, the second electrode, the conductive or semiconductive intermediate layer, the first resistance-switching layer, and the second resistance-switching layer;
a plurality of word lines and bit lines;
each resistance-switching memory cell having one end in communication with a respective bit line of the plurality of bit lines, and another end in communication with a respective word line of the plurality of word lines; and
control circuitry in communication with the plurality of word lines and bit lines, the control circuitry applies a voltage to at least one of the resistance-switching memory cells via the respective bit line and the word line thereof, to cause the resistance-switching memory element of the at least one of the resistance-switching memory cells to switch from one resistance state to another resistance state.
19. The memory device of claim 18 , wherein:
the memory array is monolithic three-dimensional array that includes multiple levels of resistance-switching memory cells, each memory level includes multiple resistance-switching memory cells in a cross-point array.
20. The memory device of claim 18 , wherein, for each resistance-switching memory cell:
the conductive or semiconductive intermediate layer and the first and second resistance-switching layers are one of L-shaped and U-shaped.
21. The memory device of claim 18 , wherein, for each resistance-switching memory cell:
the lateral arrangement is face-to-face.
22. The memory device of claim 18 , wherein, for each resistance-switching memory cell:
the lateral arrangement is end-to-end.