Memory Device

• US 20100084625A1
• Filed: 10/02/2008
• Published: 04/08/2010
• Est. Priority Date: 10/02/2008
• Status: Active Grant

• Current Assignee: Carlow Innovations, LLC
• Original Assignee: Ovonyx Incorporated (Micron Technology, Inc.)
• Inventors: Czubatyj, Wolodymyr, Wicker, Guy
• Granted Patent: US 8,344,348 B2
• Time in Patent Office: Days
• US Class Current: 257/4
• CPC Class Codes: H10B 63/24 of the Ovonic threshold switching type
• CPC Class Codes: H10N 70/20 Multistable switching devices, e.g. memristors
• CPC Class Codes: H10N 70/231 based on solid-state phase change, e.g. between amorphous and crystalline phases, Ovshinsky effect
• CPC Class Codes: H10N 70/826 adapted for essentially vertical current flow, e.g. sandwich or pillar type devices
• CPC Class Codes: H10N 70/8413 adapted for resistive heating
• CPC Class Codes: H10N 70/8825 Selenides, e.g. GeSe
• CPC Class Codes: H10N 70/8828 Tellurides, e.g. GeSbTe

Abstract

An electrical device includes a first electrode and a second electrode. A first active material is between the first electrode and second electrode. A second active material is between the first electrode and second electrode. A nonlinear electrode material is disposed between the first electrode and the second electrode. The nonlinear electrode material is electrically in series with the first electrode, the first active material, the second active material, and the second electrode. The first electrode and the first active material undergo no chemical or electrochemical reaction when current passes between the first electrode and the second electrode.

Claims

1. An electrical device comprising:

a first electrode;

a second electrode;

a first active material disposed between said first electrode and said second electrode;

a second active material disposed between said first electrode and said second electrode; and

a nonlinear resistive material disposed between said first electrode and said second electrode, said nonlinear resistive material being electrically in series with said first electrode, said first active material, said second active material, and said second electrode.

2. The electrical device of claim 1, wherein said first active material is a programmable resistance material, a phase-change material, or a chalcogenide material.

3. The electrical device of claim 2, wherein said first active material comprises one or more elements selected from the group consisting of Se and Te and one or more elements selected from the group consisting of Ge, Sb, In, and Bi.

4. The electrical device of claim 2, wherein said second active material comprises a switchable material, said switchable material having a resistive state and a conductive state, said switchable material switching from said resistive state to said conductive state upon application of a critical voltage between said first electrode and said second electrode.

5. The electrical device of claim 4, wherein said switchable material comprises a chalcogen element and one or more elements selected from the group consisting of Ge, As, Si, and In.

6. The electrical device of claim 4, wherein said switchable material is a threshold switching material, said threshold switching material having a threshold voltage, said threshold voltage corresponding to said critical voltage.

7. The electrical device of claim 4, wherein said switchable material switches from said conductive state to said resistive state upon removal of said applied voltage.

8. The electrical device of claim 4, wherein said nonlinear resistive material comprises carbon and nitrogen.

9. The electrical device of claim 8, wherein said nonlinear resistive material is formed by sputtering a carbon-containing material in the presence of a gas phase ambient that includes nitrogen gas.

10. The electrical device of claim 9, wherein the partial pressure of said nitrogen gas in said gas phase ambient is at least 20%.

11. The electrical device of claim 9, wherein the partial pressure of said nitrogen gas in said gas phase ambient is at least 40%.

12. The electrical device of claim 4, wherein said nonlinear resistive material has a first state and a second state, said second state being more conductive than said first state, said nonlinear resistive material transforming from said first state to said second state upon application of a turn-on voltage.

13. The electrical device of claim 12, wherein said transformation from said first state to said second state occurs without a discontinuity in voltage or current.

14. The electrical device of claim 12, wherein said transformation from said first state to said second state occurs at an approximately constant voltage.

15. The electrical device of claim 12, wherein said transformation from said first state to said second state is accompanied by an increase in current.

16. The electrical device of claim 12, wherein the thickness of said nonlinear resistive material is such that said turn-on voltage and said critical voltage differ by less than 1 volt.

17. The electrical device of claim 12, wherein the thickness of said nonlinear resistive material is such that said turn-on voltage and said critical voltage differ by less than 0.5 volt.

18. The electrical device of claim 12, wherein the thickness of said nonlinear resistive material is such that said turn-on voltage and said critical voltage differ by less than 0.1 volt.

19. The electrical device of claim 12, wherein said first state of said nonlinear resistive material is more conductive than said resistive state of said switchable material.

20. The electrical device of claim 19, wherein said first state of said nonlinear resistive material is less conductive than said conductive state of said switchable material.

21. The electrical device of claim 4, wherein said first active material does not experience a discontinuity in current or voltage upon said switching of said switchable material.

22. The electrical device of claim 1, wherein said nonlinear resistive material is interconnected between said first electrode and said first active material and said second active material is interconnected between said first active material and said second electrode.

23. The electrical device of claim 1, wherein said nonlinear resistive material is interconnected between said first active material and said second active material.

24. The electrical device of claim 1, further comprising a bottom interconnect, said first electrode being interconnected between said bottom interconnect and said first active material.

25. The electrical device of claim 1, further comprising:

a first insulator disposed on said nonlinear resistive material, said first insulator having a pore therethrough, said first active material occupying said pore and contacting said nonlinear resistive material.

26. The electrical device of claim 25, wherein said nonlinear resistive material contacts said first electrode.

27. The electrical device of claim 25, wherein said second active material contacts said first active material.