Guided path for forming a conductive filament in RRAM

Patent metadata

Field	Value
Publication number	US-9972778-B2
Application number	US-201414573817-A
Country	US
Kind code	B2
Filing date	Dec 17, 2014
Priority date	May 2, 2012
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

A method of forming a non-volatile memory device, includes forming a first electrode above a substrate, forming a dielectric layer overlying the first electrode, forming an opening structure in a portion of the dielectric layer to expose a surface of the first electrode having an aspect ratio, forming a resistive switching material overlying the dielectric layer and filling at least a portion of the opening structure using a deposition process, the resistive switching material having a surface region characterized by a planar region and an indent structure, the indent structure overlying the first electrode, maintaining a first thickness of resistive switching material between the planar region and the first electrode, maintaining a second thickness of resistive switching material between the indent structure and the first electrode, wherein the first thickness is larger than the second thickness, and forming a second electrode overlying the resistive switching material including the indent structure.

First claim

What is claimed is:

1. A resistive switching device for a non-volatile memory device, comprising:
a first electrode;
a resistive switching material configured in an opening region in a dielectric material overlying the first electrode, the resistive switching material being characterized by a surface region having a planar region and an indent structure, wherein at least a portion of the planar region being configured overlying the first electrode and having a distance between the planar region and a top surface of the first electrode, and the indent structure being configured overlying the first electrode and having a thickness of resistive switching material relative to the first electrode that is less than the distance; and
a second electrode overlying the resistive switching material including the indent structure;
and wherein in response to an electrical stimulus applied to the non-volatile memory device, the indent structure causes a path for a filament structure derived from the second electrode to preferentially form within the resistive switching material at a region of the indent structure.

2. The resistive switching device of claim 1 wherein the first electrode comprises a p+ polysilicon material.

3. The resistive switching device of claim 1 wherein the resistive switching material comprises an amorphous silicon material having an intrinsic semiconductor characteristic, wherein the amorphous silicon material is not intentionally doped.

4. The resistive switching device of claim 1 wherein second electrode comprises an active metal material selected from a group consisting of: silver, gold, palladium, platinum, copper, aluminum, nickel, and zinc.

5. The resistive switching device of claim 1 wherein the indent structure comprises a tapered region directed towards the first electrode.

6. The resistive switching device of claim 1 wherein the filament structure causes the resistive switching material to change from a high resistance state to a low resistance state upon application of the electrical stimulus to the non-volatile memory device.

7. The resistive switching device of claim 1 wherein the resistive switching material comprises metal material from the second electrode disposed within the path.

8. The resistive switching device of claim 1 wherein the first electrode comprises a material selected from a group consisting of Ti, TiN, WN, TaN.

9. The resistive switching device of claim 1
wherein the resistive switching material is not intentionally doped as deposited and comprises a plurality of defect sites; and
wherein metal particles from the second electrode diffuse into defect sites in the resistive switching material.

10. The resistive switching device of claim 1 wherein a bottom surface of the second electrode fills a tapered region of the indent structure and is non-planar, and a top surface of the second electrode is substantially planar.

11. A device having a non-volatile memory device, comprising:
a first dielectric material disposed adjacent to a substrate and having a first surface;
a first electrode comprising first electrode material disposed adjacent to a first portion of the first surface of the first dielectric material and having a first surface;
a second dielectric material adjacent to a second portion of the first surface of the first dielectric material and having a first surface;
a resistive switching material adjacent to and in contact with at least a portion of the first surface of the first electrode material and at least a portion of the first surface of the second dielectric material, wherein the resistive switching material having a first surface, and wherein the resistive switching material comprises a plurality of defects and as-deposited is not intentionally doped; and
a second electrode comprising a second electrode material disposed adjacent to and in contact with the first surface of the resistive switching material, wherein the second electrode material comprises a plurality of metal particles that are configured to be diffused within the resistive switching material upon application of a bias voltage; and
wherein metal particles from the plurality of metal particles are disposed within the plurality of defects in the resistive switching material.

12. The device of claim 11
wherein the first surface of the resistive switching material comprises a portion disposed above the portion of the first surface of the first electrode material and includes an indent structure, and
wherein an average thickness of the resistive switching material within the portion is larger than a thickness of the resistive switching material within the indent structure.

13. The device of claim 11 further comprising a control circuitry disposed on the substrate, wherein the control circuitry is coupled to the first electrode.

14. The device of claim 13 wherein the control circuitry is selected from a group consisting of: write circuitry, read circuitry, erase circuitry.

15. The device of claim 11 wherein the first electrode comprises a material selected from a group consisting of Ti, TiN, WN, TaN.

16. The device of claim 15 wherein second electrode material comprises an active metal material selected from a group consisting of: gold, palladium, platinum, copper, aluminum, and nickel.

17. The device of claim 11 wherein the resistive switching material is selected from a group consisting of: an undoped silicon-bearing material, an intrinsic semiconductor material.

18. The device of claim 11 wherein the metal particles from the plurality of metal particles from the first electrode are disposed along a predetermined path within the resistive switching material.

19. The device of claim 11 wherein a resistance associated with the resistive switching material as-deposited is different from a resistance associated with the resistive switching material having the metal particles disposed therein.

20. The device of claim 11 wherein the metal particles disposed within the resistive switching material form a filament structure extending from the second electrode towards the first electrode.

Assignees

• Crossbar Inc

Inventors

• Jo Sung Hyun

Classifications

• H10P14/40

  of conductive or resistive materials · CPC title

• H01L45/1266

  Electricity · mapped topic

• H01L45/1675

  Electricity · mapped topic

• H01L45/1683

  Electricity · mapped topic

• H01L45/1253

  Electricity · mapped topic