Conductive metal oxide structures in non-volatile re-writable memory devices
View Patent ↗A memory cell including a memory element comprising an electrolytic insulator in contact with a conductive metal oxide (CMO) is disclosed. The CMO includes a crystalline structure and can comprise a pyrochlore oxide, a conductive binary oxide, a multiple B-site perovskite, and a Ruddlesden-Popper structure. The CMO includes mobile ions that can be transported to/from the electrolytic insulator in response to an electric field of appropriate magnitude and direction generated by a write voltage applied across the electrolytic insulator and CMO. The memory cell can include a non-ohmic device (NOD) that is electrically in series with the memory element. The memory cell can be positioned between a cross-point of conductive array lines in a two-terminal cross-point memory array in a single layer of memory or multiple vertically stacked layers of memory that are fabricated over a substrate that includes active circuitry for data operations on the array layer(s).
1. A pyrochlore non-volatile memory cell, comprising:
a first terminal structure;
a second terminal structure; and
a memory element electrically in series with the first and second terminal structures and operative to store data as a plurality of conductivity profiles, the memory element including
an electrolytic insulator in contact with the first terminal structure and including a first thickness configured to allow tunneling conduction, and
a conductive metal oxide (CMO) including mobile oxygen ions and made from a pyrochlore oxide material having a crystalline structure, the CMO is in contact with the electrolytic insulator and with the second terminal structure,
wherein the pyrochlore oxide material includes a form A 2 B 2 O 7 , where O represents oxygen, A represents at least one rare-earth element, and B represents a selected one of a rare-earth element or a transition metal element.
2. The pyrochlore non-volatile memory cell of claim 1 , wherein the first thickness is approximately 50 Å or less.
3. The pyrochlore non-volatile memory cell of claim 2 , wherein the electrolytic insulator comprises yttria stabilized zirconia (YSZ).
4. The pyrochlore non-volatile memory cell of claim 2 , wherein the electrolytic insulator comprises zirconium oxide.
5. The pyrochlore non-volatile memory cell of claim 2 , wherein the electrolytic insulator comprises hafnium oxide.
6. The pyrochlore non-volatile memory cell of claim 2 , wherein the electrolytic insulator comprises gadolinium oxide.
7. The pyrochlore non-volatile memory cell of claim 2 , wherein the electrolytic insulator comprises erbium oxide.
8. The pyrochlore non-volatile memory cell of claim 1 and further comprising: a non-ohmic device electrically in series with the memory element and with the first and second terminal structures.
9. The pyrochlore non-volatile memory cell of claim 1 , wherein the first terminal structure is electrically coupled with only one of a plurality of first conductive array lines in a two-terminal cross-point memory array and the second terminal structure is electrically coupled with only one of a plurality of second conductive array lines in the two-terminal cross-point memory array.
10. The pyrochlore non-volatile memory cell of claim 9 , wherein the two-terminal cross-point memory array is connected with and is positioned above a substrate including active circuitry electrically coupled with the plurality of first and second conductive array lines and operative to perform data operation on the two-terminal cross-point memory array.
11. A binary oxide non-volatile memory cell, comprising:
a first terminal structure;
a second terminal structure; and
a memory element electrically in series with the first and second terminal structures and operative to store data as a plurality of conductivity profiles, the memory element including
an electrolytic insulator in contact with the first terminal structure and including a first thickness configured to allow tunneling conduction, and
a conductive metal oxide (CMO) including mobile oxygen ions and made from a conductive binary oxide material having a crystalline structure, the CMO is in contact with the electrolytic insulator and with the second terminal structure,
wherein the conductive binary oxide material includes a form A X O Y , where O represents oxygen and A represents a metal.
12. The binary oxide non-volatile memory cell of claim 11 , wherein the conductive binary oxide material comprises tin oxide.
13. The binary oxide non-volatile memory cell of claim 11 , wherein the conductive binary oxide material comprises zinc oxide.
14. The binary oxide non-volatile memory cell of claim 11 , wherein the electrolytic insulator includes vacancies operative to reversibly receive a portion of the mobile oxygen ions in response to a write voltage applied across the first and second terminal structures.
15. The binary oxide non-volatile memory cell of claim 11 , wherein the conductive binary oxide material comprises a doped titanium oxide.
16. The binary oxide non-volatile memory cell of claim 15 , wherein the titanium oxide is doped with niobium.
17. The binary oxide non-volatile memory cell of claim 11 , wherein the first thickness is approximately 50 Å or less.
18. The binary oxide non-volatile memory cell of claim 17 , wherein the electrolytic insulator comprises yttria stabilized zirconia (YSZ).
19. The binary oxide non-volatile memory cell of claim 17 , wherein the electrolytic insulator comprises zirconium oxide.
20. The binary oxide non-volatile memory cell of claim 17 , wherein the electrolytic insulator comprises hafnium oxide.
21. The binary oxide non-volatile memory cell of claim 17 , wherein the electrolytic insulator comprises gadolinium oxide.
22. The binary oxide non-volatile memory cell of claim 17 , wherein the electrolytic insulator comprises erbium oxide.
23. The binary oxide non-volatile memory cell of claim 17 , wherein the electrolytic insulator comprises yttrium oxide.
24. The binary oxide non-volatile memory cell of claim 11 and further comprising: a non-ohmic device electrically in series with the memory element and with the first and second terminal structures.
25. The binary oxide non-volatile memory cell of claim 11 , wherein the first terminal structure is electrically coupled with only one of a plurality of first conductive array lines in a two-terminal cross-point memory array and the second terminal structure is electrically coupled with only one of a plurality of second conductive array lines in the two-terminal cross-point memory array.
26. The binary oxide non-volatile memory cell of claim 25 , wherein the two-terminal cross-point memory array is connected with and is positioned above a substrate including active circuitry electrically coupled with the plurality of first and second conductive array lines and operative to perform data operation on the two-terminal cross-point memory array.
27. A Ruddlesden-Popper non-volatile memory cell, comprising:
a first terminal structure;
a second terminal structure; and
a memory element electrically in series with the first and second terminal structures and operative to store data as a plurality of conductivity profiles, the memory element including
an electrolytic insulator in contact with the first terminal structure and including a first thickness operative to allow tunneling conduction, and
a conductive metal oxide (CMO) including mobile oxygen ions and made from a Ruddlesden-Popper material having a crystalline structure, the CMO is in contact with the electrolytic insulator and with the second terminal structure.
28. The Ruddlesden-Popper non-volatile memory cell or claim 27 , wherein the material having the Ruddlesden-Popper structure includes a form ABO 3 , where O represents oxygen, A represents an alkaline earth metal element, and B represents a transition metal element.
29. The Ruddlesden-Popper non-volatile memory cell or claim 27 , wherein the material having the Ruddlesden-Popper structure includes a form AO(ABO 3 )n, where O represents oxygen, A represents at least one alkaline earth metal element, B represents at least one transition metal element, and n represents a Ruddlesden-Popper phase.
30. The Ruddlesden-Popper non-volatile memory cell of claim 27 , wherein the first thickness is approximately 50 Å or less.
31. The Ruddlesden-Popper non-volatile memory cell of claim 30 , wherein the electrolytic insulator comprises yttria stabilized zirconia (YSZ).
32. The Ruddlesden-Popper non-volatile memory cell of claim 30 , wherein the electrolytic insulator comprises zirconium oxide.
33. The Ruddlesden-Popper non-volatile memory cell of claim 30 , wherein the electrolytic insulator comprises hafnium oxide.
34. The Ruddlesden-Popper non-volatile memory cell of claim 30 , wherein the electrolytic insulator comprises gadolinium oxide.
35. The Ruddlesden-Popper non-volatile memory cell of claim 30 , wherein the electrolytic insulator comprises erbium oxide.
36. The Ruddlesden-Popper non-volatile memory cell of claim 27 and further comprising: a non-ohmic device electrically in series with the memory element and with the first and second terminal structures.
37. The Ruddlesden-Popper non-volatile memory cell of claim 27 , wherein the first terminal structure is electrically coupled with one of a plurality of first conductive array lines in a two-terminal cross-point memory array and the second terminal structure is electrically coupled with one of a plurality of second conductive array lines in the two-terminal cross-point memory array.
38. The Ruddlesden-Popper non-volatile memory cell of claim 37 , wherein the two-terminal cross-point memory array is connected with and is positioned above a substrate including active circuitry electrically coupled with the plurality of first and second conductive array lines and operative to perform data operation on the two-terminal cross-point memory array.
39. A multiple B-site non-volatile memory cell, comprising:
a first terminal structure;
a second terminal structure; and
a memory element electrically in series with the first and second terminal structures and operative to store data as a plurality of conductivity profiles, the memory element including
an electrolytic insulator in contact with the first terminal structure and including a first thickness operative to allow tunneling conduction, and
a conductive metal oxide (CMO) including mobile oxygen ions and made from a multiple B-site perovskite material including a plurality of perovskite unit cells, the CMO is in contact with the electrolytic insulator and with the second terminal structure,
the multiple B-site perovskite material includes a form A X (B 1 ,B 2 ) Y O Z , where A X represents one or more elements selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, calcium, strontium, and barium that are positioned at A-sites in the plurality of perovskite unit cells, B 1 represents a first transition metal element positioned at B-sites in a first portion of the plurality of perovskite unit cells, B 2 represents a second transition metal element positioned at B-sites in a second portion of the plurality of perovskite unit cells, the second transition metal element is different than the first transition metal element, where O represents oxygen, where X can be any number, where Y is typically 1, and where Z is typically 3.
40. The multiple B-site non-volatile memory cell of claim 39 , wherein the first thickness is approximately 50 Å or less.
41. The multiple B-site non-volatile memory cell of claim 39 , wherein the electrolytic insulator comprises yttria stabilized zirconia (YSZ).
42. The multiple B-site non-volatile memory cell of claim 39 , wherein the electrolytic insulator comprises zirconium oxide.
43. The multiple B-site non-volatile memory cell of claim 39 , wherein the electrolytic insulator comprises hafnium oxide.
44. The multiple B-site non-volatile memory cell of claim 39 , wherein the electrolytic insulator comprises gadolinium oxide.
45. The multiple B-site non-volatile memory cell of claim 39 , wherein the electrolytic insulator comprises erbium oxide.
46. The multiple B-site non-volatile memory cell of claim 39 and further comprising: a non-ohmic device electrically in series with the memory element and with the first and second terminal structures.
47. The multiple B-site non-volatile memory cell of claim 39 , wherein the first terminal structure is electrically coupled with one of a plurality of first conductive array lines in a two-terminal cross-point memory array and the second terminal structure is electrically coupled with one of a plurality of second conductive array lines in the two-terminal cross-point memory array.
48. The multiple B-site non-volatile memory cell of claim 47 , wherein the two-terminal cross-point memory array is connected with and is positioned above a substrate including active circuitry electrically coupled with the plurality of first and second conductive array lines and operative to perform data operation on the two-terminal cross-point memory array.
49. The multiple B-site non-volatile memory cell of claim 39 , wherein the multiple B-site perovskite material includes a crystalline structure.
50. The multiple B-site non-volatile memory cell of claim 49 , wherein the crystalline structure does not comprise a single crystalline structure.