Vertical array of resistive switching devices having a tunable oxygen vacancy concentration

Patent metadata

Field	Value
Publication number	US-10700129-B2
Application number	US-201816015934-A
Country	US
Kind code	B2
Filing date	Jun 22, 2018
Priority date	Jun 22, 2018
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

Embodiments of the invention are directed to a vertical resistive device. A non-limiting example of the vertical resistive device includes a conductive horizontal electrode, an opening extending through the horizontal electrode, a filament region positioned within the opening and communicatively coupled to a sidewall of the horizontal electrode, and a conductive vertical electrode positioned within the opening and communicatively coupled to the filament region. The vertical electrode includes a first conductive alloy material. Oxygen vacancy formation in the filament region is controlled by the first conductive alloy material of the vertical electrode. A room temperature resistivity of the first conductive alloy material is below about 5×10−8 ohm meters and controlled by at least one of the metals that form the first conductive alloy material.

First claim

What is claimed is:

1. A vertical resistive device comprising:
a conductive horizontal electrode;
an opening extending through the horizontal electrode;
a filament region positioned within the opening and communicatively coupled to a sidewall of the horizontal electrode;
a barrier region positioned within the opening and communicatively coupled to the filament region; and
a conductive vertical electrode positioned within the opening and communicatively coupled through the barrier region to the filament region;
wherein:
the vertical electrode comprises a first conductive alloy material;
oxygen vacancy formation in the filament region is controlled by the first conductive alloy material of the vertical electrode;
a thickness dimension of the barrier region; and
a room temperature resistivity of the first conductive alloy material is below about 5×10 −8 ohm meters and controlled by at least one element that forms the first conductive alloy material.

2. The device of claim 1 , wherein the at least one of the elements that form the first conductive alloy material comprises aluminum.

3. The device of claim 2 , wherein the first conductive alloy material comprises a titanium aluminum alloy or a cobalt aluminum alloy.

4. The device of claim 1 , wherein:
oxygen vacancy formation in the filament region comprises diffusion of oxygen molecules across the barrier region; and
the diffusion of oxygen molecules across the barrier region is tuned by selecting:
a barrier material that forms the barrier region; and
the thickness dimension of the barrier metal layer.

5. The device of claim 1 , wherein the barrier material is configured to prevent alloying of the filament region with the vertical electrode.

6. The device of claim 5 , wherein the barrier material is selected from a group consisting of titanium nitride (TiN), tantalum nitride (TaN), hafnium nitride (HfN), niobium nitride (NbN), tungsten nitride (WN), and combinations thereof.

7. The device of claim 1 further comprising:
a first dielectric layer across from the horizontal electrode; and
a second dielectric layer on an opposite side of the horizontal electrode than the first dielectric layer;
wherein:
the opening also extends through the first dielectric layer and the second dielectric layer; and
sidewalls of the opening comprise sidewalls of the first dielectric layer and sidewalls of the second dielectric layer.

8. The device of claim 7 , wherein:
the first dielectric layer and the second dielectric layer comprise silicon nitride (SiN) or silicon dioxide (SiO 2 );
the filament region comprises a metal oxide comprising a compound selected from the group consisting of HfO 2 , Ta 2 O 5 , and ZrO 2 .

9. The device of claim 1 further including a resistive switching device (RSD) comprising:
a bottom electrode comprising the horizontal electrode;
the filament region; and
a top electrode comprising the vertical electrode.

10. The device of claim 1 , wherein the conductive horizontal electrode comprises titanium nitride (TiN) or tungsten (W).

11. A method of fabricating a vertical resistive device, the method comprising:
forming a conductive horizontal electrode;
forming an opening that extends through the horizontal electrode;
depositing a filament region within the opening such that the filament region is communicatively coupled to a sidewall of the horizontal electrode;
depositing a barrier region within the opening such that the barrier region is communicatively coupled to the filament region; and
forming a conductive vertical electrode within a remaining portion of the opening such that the vertical electrode is communicatively coupled to the barrier region;
wherein:
the vertical electrode comprises a first conductive alloy material;
oxygen vacancy formation in the filament region is controlled by a thickness dimension of the barrier region and by the first conductive alloy material of the vertical electrode; and
a room temperature resistivity of the first conductive alloy material is below about 5×10 −8 ohm meters and controlled by at least one element that forms the first conductive alloy material.

12. The method of claim 11 , wherein the at least one element that forms the first conductive alloy material comprises aluminum.

13. The method of claim 12 , wherein the first conductive alloy material comprises a titanium aluminum alloy or a cobalt aluminum alloy.

14. The method of claim 11 , wherein forming the conductive vertical electrode comprises:
depositing a wetting layer over the barrier layer;
depositing a fill metal over the wetting layer; and
reflowing the wetting layer and the fill metal to form an alloy of the wetting layer and the fill metal.

15. The method of claim 14 , wherein the barrier region comprises a barrier material configured to prevent alloying of the filament region with the wetting layer and the fill metal.

16. The method of claim 15 , wherein the barrier material is selected from a group consisting of titanium nitride (TiN), tantalum nitride (TaN), hafnium nitride (HfN), niobium nitride (NbN), tungsten nitride (WN), and combinations thereof.

17. The method of claim 11 further comprising:
forming a first dielectric layer across from the horizontal electrode; and
forming a second dielectric layer on an opposite side of the horizontal electrode than the first dielectric layer;
wherein:
the opening also extends through the first dielectric layer and the second dielectric layer; and
sidewalls of the opening comprise sidewalls of the first dielectric layer and sidewalls of the second dielectric layer.

18. The method of claim 17 , wherein:
the first dielectric layer and the second dielectric layer comprise silicon nitride (SiN) or silicon dioxide (SiO 2 );
the filament region comprises a metal oxide comprising a compound selected from the group consisting of HfO 2 , Ta 2 O 5 , and ZrO 2 .

19. The method of claim 11 , wherein the vertical resistive device comprises a resistive switching device (RSD) comprising:
a bottom electrode comprising the horizontal electrode;
the filament region; and
a top electrode comprising the vertical electrode.

20. The method of claim 11 , wherein the horizontal electrode comprises titanium nitride (TiN) or tungsten (W).

Assignees

• IBM

Inventors

• Ando Takashi
• Lee Choonghyun

Classifications

• H10N70/841

  Electrodes · CPC title

• H10N70/046

  by diffusion, e.g. photo-dissolution · CPC title

• H10N70/823

  adapted for essentially horizontal current flow, e.g. bridge type devices · CPC title

• H10N70/8833

  Binary metal oxides, e.g. TaOx · CPC title

• H10N70/24

  based on migration or redistribution of ionic species, e.g. anions, vacancies · CPC title