Memory device and method of manufacturing the device by simultaneously conditioning transition metal oxide layers in a plurality of memory cells

• US 20060267086A1
• Filed: 05/31/2005
• Published: 11/30/2006
• Est. Priority Date: 05/31/2005
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Koburger, Charles W. III, Hakey, Mark C., Horak, David V., Lam, Chung H., Holmes, Steven J., Meijer, Gerhard I., Furukawa, Toshijaru
• Granted Patent: US 7,256,415 B2
• Time in Patent Office: Days
• US Class Current: 257/334
• CPC Class Codes: H10B 63/20 comprising selection components having two electrodes, e.g. diodes
• CPC Class Codes: H10B 63/80 Arrangements comprising multiple bistable or multi-stable switching components of the same type on a plane parallel to the substrate, e.g. cross-point arrays
• CPC Class Codes: H10B 69/00 Erasable-and-programmable ROM [EPROM] devices not provided for in groups H10B41/00 - H10B63/00, e.g. ultraviolet erasable-and-programmable ROM [UVEPROM] devices
• CPC Class Codes: H10N 70/20 Multistable switching devices, e.g. memristors
• CPC Class Codes: H10N 70/826 adapted for essentially vertical current flow, e.g. sandwich or pillar type devices
• CPC Class Codes: H10N 70/8836 Complex metal oxides, e.g. perovskites, spinels
• CPC Class Codes: Y10S 438/90 Bulk effect device making

Abstract

Disclosed are non-volatile memory devices that incorporate a series of single or double memory cells. The single memory cells are essentially “U” shaped. The double memory cells comprise two essentially “U” shaped memory cells. Each memory cell comprises a memory element having a bi-stable layer sandwiched between two conductive layers. A temporary conductor may be applied to a series of cells and used to bulk condition the bi-stable layers of the cells. Also, due to the “U” shape of the cells, a cross point wire array may be used to connect a series of cells. The cross point wire array allows the memory elements of each cell to be individually identified and addressed for storing information and also allows for the information stored in the memory elements in all of the cells in the series to be simultaneously erased using a block erase process.

Claims

1. An integrated circuit structure comprising:

a single memory cell comprising;

a memory element having a first top electrical contact and a first bottom surface, wherein said memory element comprises;

a first conductive layer;

a bi-stable layer on said first conductive layer; and

a second conductive layer on said bi-stable layer; and

a conductive section having a second top electrical contact and a second bottom surface and comprising a conductive material;

wherein said conductive section is parallel to said memory element and wherein said bottom surface of said memory element is electrically connected to said bottom surface of said conductive section.

2. The structure of claim 1, further comprising a diode electrically connecting said first bottom surface and said second bottom surface to establish an electric current between said memory element and said conductive section.

3. The structure of claim 1, wherein said bi-stable layer comprises a conditioned transition metal oxide.

4. The structure of claim 1, wherein said bi-stable layer comprises a conditioned perovskite material.

5. The structure of claim 1, wherein said bi-stable layer comprises a material with a bi-stable, programmable, electrical resistance.

6. The structure of claim 5, wherein said programmable electrical resistance of said bi-stable layer is adapted to allow information to be repeatedly stored in and erased from said memory element.

7. The structure of claim 6, further comprising:

a series of said single memory cells separated by an insulating material; and

a cross point wire array connecting said single memory cells in said series,

wherein said cross point wire array comprises first direction wires connecting said first top electrical contacts of said single memory cells in said series and second direction wires connecting said second top electrical contacts of said single memory cells in said series.

8. The structure of claim 7, wherein said cross point wire array is adapted to allow a block erase process to be used to erase said information stored in said memory elements of all of said single memory cells of said series.

9. An integrated circuit structure comprising:

a double memory cell comprising;

a first memory element having a first top electrical contact and a first bottom surface;

a second memory element parallel to said first memory element and having a second top electrical contact and a second bottom surface;

wherein said first memory element and said second memory element each comprise;

a first conductive layer;

a bi-stable layer on said first conductive layer; and

a second conductive layer on said bi-stable layer; and

a conductive section having a third top electrical contact and a third bottom surface and comprising a conductive material;

wherein said conductive section is parallel to and disposed between said first memory element and said second memory element and wherein said third bottom surface is electrically connected to said first bottom surface and said second bottom surface.

10. The structure of claim 9, further comprising:

a diode electrically connected between said third bottom surface and said first bottom surface to establish an electric current; and

another diode electrically connected between said third bottom surface and said second bottom surface to establish an electric current.

11. The structure of claim 9, wherein said bi-stable layer comprises a conditioned transition metal oxide.

12. The structure of claim 9, wherein said bi-stable layer comprises a conditioned perovskite material.

13. The structure of claim 9, wherein said bi-stable layer comprises a material with a bi-stable, programmable, electrical resistance.

14. The structure of claim 13, wherein said programmable electrical resistance of said bi-stable layer is adapted to allow information to be repeatedly stored in and erased from said first memory element and said second memory element.

15. The structure of claim 14, further comprising:

a series of said double memory cells separated by an insulating material; and

a cross point wire array connecting said double memory cells in said series,

wherein said cross point wire array comprises first direction wires connecting said first top electrical contacts of said double memory cells in said series, other first direction wires connecting said second top electrical contacts of said double memory cells in said series and second direction wires connecting said third top electrical contacts of said double memory cells in said series.

16. The structure of claim 15, wherein said cross point wire array is adapted to allow a block erase process to be used to erase said information stored in said first memory elements and said second memory elements of said double memory cells in said series.

17. A method of forming a memory device, said method comprising:

simultaneously forming a series of single memory cells, wherein forming of each of said single memory cells in said series comprises;

forming two parallel holes in an insulating layer;

forming a memory element with a first top electrical contact in one of said two parallel holes by filling said one of said two parallel holes with a first conductive layer, a transition metal oxide layer on said first conductive layer, and a second conductive layer on said transition metal oxide layer,

forming a conductive section with a second top electrical contact in another of said two parallel holes by filling said other of said two parallel holes with a conductive material; and

electrically connecting said memory element and said conductive section;

simultaneously conditioning all of said transition metal oxide layers of said memory elements of said single memory cells in said series,

wherein said conditioning causes said transition metal oxide layers to exhibit a bi-stable electrical resistance.

18. The method of claim 17, wherein said process of simultaneously conditioning all of said transition metal oxide layers comprises:

connecting said first top electrical contacts of said memory elements of each of said single memory cells in said series to said second top electrical contacts of said conductive sections of an adjacent single memory cell in said series with a temporary conductor,

connecting said temporary conductor at an end of said series to a power source adapted to output a current through said series of said single memory cells.

19. The method of claim 18, further comprising:

reducing the voltage from said power source as said transition metal oxide layer of each of said single memory cells in said series is conditioned.

20. The method of claim 19, further comprising:

removing said temporary conductor after conditioning said transition metal oxide layer of said memory element of all of said single memory cells in said series.

21. The method of claim 17, further comprising:

electrically connecting said single memory cells in said series using a cross point wire array.

22. A method of forming a memory device, said method comprising:

simultaneously forming a series of double memory cells, wherein forming of each of said double memory cells in said series comprises;

forming three parallel holes in an insulator layer;

forming a first memory element with a first top electrical contact and a second memory element with a second top electrical contact in two of said three parallel holes by filling said two of said three parallel holes with a first conductive layer, a transition metal oxide layer on said first conductive layer, and a second conductive layer on said transition metal oxide layer,

forming a conductive section with a third top electrical contact in another of said three parallel holes by filling said other of said three parallel holes with a conductive material; and

electrically connecting said conductive section to each of said first memory element and said second memory element;

simultaneously conditioning said transition metal oxide layer of said first memory element of each of said double memory cells in said series; and

simultaneously conditioning said transition metal oxide layer of said second memory element of each of said double memory cells in said series,

wherein said conditioning causes said transition metal oxide layers to exhibit a bi-stable electrical resistance.

23. The method of claim 22, wherein said process of simultaneously conditioning said transition metal oxide layer of said first memory element comprises:

connecting said first top electrical contacts from said double memory cells in said series to said third top electrical contact of an adjacent double memory cell in said series with a temporary conductor;

connecting said temporary conductor at an end of said series to a power source adapted to output a electric current;

reducing the voltage output from said power source as each of said transition metal oxide layers of said first memory element from each of said double memory cells is conditioned; and

removing said temporary conductor after conditioning said transition metal oxide layer of said first memory element of all of said double memory cells in said series.

24. The method of claim 23, wherein said process of simultaneously conditioning said transition metal oxide layer of said second memory element comprises, after said process of simultaneously conditioning said transition metal oxide layer of said first memory element,

connecting said second top electrical contact from each of said double memory cells in said series to said third top electrical contact of an adjacent double memory cell in said series with a temporary conductor;

connecting said temporary conductor at an end of said series to a power source adapted to output a electric current;

reducing the voltage output from said power source as each of said transition metal oxide layers of said second memory element from each of said double memory cells is conditioned; and

removing said temporary conductor after conditioning said transition metal oxide layer of said second memory element of all of said double memory cells in said.

25. The method of claim 22, further comprising:

electrically connecting said double memory cells in said series using a cross point wire array.