Diffusion barrier layer for resistive random access memory cells

• US 8,686,389 B1
• Filed: 10/16/2012
• Issued: 04/01/2014
• Est. Priority Date: 10/16/2012
• Status: Expired due to Fees

• Current Assignee: Intermolecular Incorporated
• Original Assignee: Intermolecular Incorporated
• Inventors: Wang, Yun, Hashim, Imran
• Primary Examiner(s): Valentine, Jami M
• Application Number:
  US13/652,742
• Publication Number:
  US 20140103282A1
• Time in Patent Office: 532 Days
• Field of Search: 257 1- 5, 257/E29.002, 438102-104, 365/163
• US Class Current: 257/2
• 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 63/84 arranged in a direction perpendicular to the substrate, e.g. 3D cell arrays
• CPC Class Codes: H10N 70/011 Manufacture or treatment of multistable switching devices
• CPC Class Codes: H10N 70/021 Formation of the switching material, e.g. layer deposition
• CPC Class Codes: H10N 70/023 by chemical vapor deposition, e.g. MOCVD, ALD
• CPC Class Codes: H10N 70/026 by physical vapor deposition, e.g. sputtering
• CPC Class Codes: H10N 70/24 based on migration or redistribution of ionic species, e.g. anions, vacancies
• CPC Class Codes: H10N 70/801 Constructional details of multistable switching devices
• CPC Class Codes: H10N 70/826 adapted for essentially vertical current flow, e.g. sandwich or pillar type devices
• CPC Class Codes: H10N 70/841 Electrodes
• CPC Class Codes: H10N 70/883 Oxides or nitrides
• CPC Class Codes: H10N 70/8833 Binary metal oxides, e.g. TaOx
• CPC Class Codes: H10N 70/8836 Complex metal oxides, e.g. perovskites, spinels

Abstract

Provided are resistive random access memory (ReRAM) cells having diffusion barrier layers formed from various materials, such as beryllium oxide or titanium silicon nitrides. Resistive switching layers used in ReRAM cells often need to have at least one inert interface such that substantially no materials pass through this interface. The other (reactive) interface may be used to introduce and remove defects from the resistive switching layers causing the switching. While some electrode materials, such as platinum and doped polysilicon, may form inert interfaces, these materials are often difficult to integrate. To expand electrode material options, a diffusion barrier layer is disposed between an electrode and a resistive switching layer and forms the inert interface with the resistive switching layer. In some embodiments, tantalum nitride and titanium nitride may be used for electrodes separated by such diffusion barrier layers.

Claims

1. A resistive random access memory cell comprising:

a first electrode layer comprising a first oxygen reactive material;

a second electrode layer comprising a second oxygen reactive material;

a resistive switching layer comprising a resistive switching material,

the resistive switching layer directly interfacing the second electrode layer; and

a diffusion barrier layer comprising an oxygen diffusion barrier material,

the diffusion barrier layer being disposed between and directly interfacing the first electrode layer and the resistive switching layer;

wherein the oxygen diffusion barrier material has predominantly covalent bonding.

2. The resistive random access memory cell of claim 1, wherein the oxygen diffusion barrier material is one of beryllium oxide or tantalum silicon nitride.

3. The resistive random access memory cell of claim 1, wherein the diffusion barrier layer has a thickness of between about 5 Angstroms and 50 Angstroms.

4. The resistive random access memory cell of claim 1, wherein the diffusion barrier layer has a thickness of between about 10 Angstroms and 30 Angstroms.

5. The resistive random access memory cell of claim 4, wherein the oxygen diffusion barrier material has a dielectric constant of between 4 and 10.

6. The resistive random access memory cell of claim 1, wherein the oxygen diffusion barrier material has a dielectric constant of between 6 and 10.

7. The resistive random access memory cell of claim 1, wherein the oxygen diffusion barrier material has a thermal conductivity of between 200 W K⁻

1 m<sup>−

1</sup> and 1000 W K<sup>−

1</sup> m<sup>−

1</sup>.

8. The resistive random access memory cell of claim 1, wherein the oxygen diffusion barrier material has a thermal conductivity of between 300 W K⁻

1 m<sup>−

1</sup> and 1000 W K<sup>−

1</sup> m<sup>−

1</sup>.

9. The resistive random access memory cell of claim 1, wherein the first oxygen reactive material is tantalum nitride.

10. The resistive random access memory cell of claim 1, wherein the second oxygen reactive material is titanium nitride.

11. The resistive random access memory cell of claim 1, wherein the first electrode layer has a thickness of less than about 500 Angstroms.

12. The resistive random access memory cell of claim 1, wherein the resistive switching material is one of hafnium oxide, aluminum oxide, titanium oxide, or zirconium oxides.

13. The resistive random access memory cell of claim 1, wherein the diffusion barrier layer is substantially free of pin holes.

14. The resistive random access memory cell of claim 1, wherein the diffusion barrier layer is substantially conformal.

15. The resistive random access memory cell of claim 1, wherein the oxygen diffusion barrier material is substantially free of oxygen vacancies.

16. The resistive random access memory cell of claim 1, wherein the resistive switching layer has a thickness of less than about 100 Angstroms.

17. The resistive random access memory cell of claim 1, wherein the resistive switching material exhibits bipolar resistive switching.

18. A resistive random access memory cell comprising:

a first electrode layer comprising titanium nitride;

a second electrode layer comprising titanium nitride;

a resistive switching layer comprising hafnium oxide,

the resistive switching layer directly interfacing the second electrode layer;

a diffusion barrier layer comprising beryllium oxide and having a thickness of less than 30 Angstroms,

the diffusion barrier layer being disposed between and directly interfacing the first electrode layer and the resistive switching layer.