Method for manufacturing memory element

• US 7,829,473 B2
• Filed: 03/18/2008
• Issued: 11/09/2010
• Est. Priority Date: 03/26/2007
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yoshizumi, Kensuke
• Primary Examiner(s): Toledo; Fernando L
• Assistant Examiner(s): Singal; Ankush K
• Application Number:
  US12/050,687
• Publication Number:
  US 20080242083A1
• Time in Patent Office: 966 Days
• Field of Search: 438/660, 438/758, 427/117, 427/58, 257/737, 257/E23.023, 257/E21.476, 257/40, 257/632, 257/296
• US Class Current: 438/758
• CPC Class Codes: H01L 27/1292 using liquid deposition, e.g. printing
• CPC Class Codes: H01L 29/40114 the electrodes comprising a conductor-insulator-conductor-insulator-semiconductor structure
• CPC Class Codes: H10B 63/00 Resistance change memory devices, e.g. resistive RAM [ReRAM] devices

Abstract

A first conductive layer is formed, a composition layer over the first conductive layer is formed by discharging a composition in which nanoparticles comprising a conductive material covered with an organic material are dispersed in a solvent, and the composition layer is dried. Subsequently, pretreatment is performed in which the organic material covering the nanoparticles, which are positioned on a surface of the composition layer, is decomposed, and then baking is performed. In this manner, a second conductive layer is formed by sintering nanoparticles which are positioned on a surface of the composition layer. A memory layer is formed between the first conductive layer and the second conductive layer using the nanoparticles covered with the organic materials to which the pretreatment is not performed.

Claims

1. A method for manufacturing a memory element, comprising the steps of:

forming a first conductive layer;

forming a composition layer over the first conductive layer by discharging a composition in which nanoparticles comprising a conductive material covered with an organic material are dispersed in a solvent;

drying the composition layer; and

decomposing the organic material covering the nanoparticles which are positioned on the surface of the composition layer such that a memory layer comprising the nanoparticles covered with the organic material and a second layer comprising the nanoparticles not covered with the organic material are formed in the composition layer, wherein the memory layer is closer to the first conductive layer than the second layer;

forming a second conductive layer by sintering of the nanoparticles not covered with the organic material in the second layer.

2. The method for manufacturing a memory element according to claim 1,

wherein reduction treatment is performed after the decomposing step.

3. The method for manufacturing a memory element according to claim 1,

wherein a grain diameter of each of the nanoparticles is greater than or equal to 1 nm and less than or equal to 200 nm.

4. The method for manufacturing a memory element according to claim 1,

wherein the organic material comprises a surfactant or a substance which can form a coordinate bond with the conductive material.

5. A method for manufacturing a memory element, comprising the steps of:

forming a first conductive layer;

forming a composition layer over the first conductive layer by discharging a composition in which nanoparticles comprising a conductive material covered with an organic material are dispersed in a solvent;

drying the composition to vaporize the solvent;

exposing a surface of the composition layer to active oxygen; and

baking the composition layer so that the surface of the composition layer is made to be a second conductive layer by sintering the nanoparticles exposed to the active oxygen and a memory layer is formed between the first conductive layer and the second conductive layer,

wherein the memory layer includes nanoparticles covered with the organic material.

6. The method for manufacturing the memory element according to claim 5,

wherein the active oxygen is generated by irradiating ozone with an ultraviolet ray.

7. The method for manufacturing a memory element according to claim 5,

wherein reduction treatment is performed after the exposing step.

8. The method for manufacturing a memory element according to claim 5,

wherein a grain diameter of each of the nanoparticles is greater than or equal to 1 nm and less than or equal to 200 nm.

9. The method for manufacturing a memory element according to claim 5,

wherein the organic material comprises a surfactant or a substance which can form a coordinate bond with the conductive material.

10. The method for manufacturing the memory element according to claim 6,

wherein the composition layer is also irradiated with the ultraviolet ray.

11. The method for manufacturing the memory element according to claim 6,

wherein the ozone is generated by irradiating oxygen with the ultraviolet ray with a wavelength of less than or equal to 240 nm.

12. The method for manufacturing the memory element according to claim 6,

wherein portions of the ozone and the active oxygen are generated by irradiating oxygen with the ultraviolet ray with a wavelength of less than or equal to 175 nm.

13. The method for manufacturing a memory element according to claim 6,

wherein irradiation with the ultraviolet ray is performed using a low-pressure mercury vapor lamp.

14. The method for manufacturing a memory element according to claim 6,

wherein irradiation with the ultraviolet ray is performed using an excimer lamp.

15. A method for manufacturing a memory element, comprising the steps of:

forming a first conductive layer;

forming a composition layer over the first conductive layer by discharging a composition in which nanoparticles comprising a conductive material covered with an organic material are dispersed in a solvent;

drying the composition layer to vaporize the solvent;

irradiating the composition layer with an ultraviolet ray in an ozone atmosphere; and

baking the composition layer so that a portion of the composition layer which is irradiated with the ultraviolet ray is made to be a second conductive layer by sintering the nanoparticles and a memory layer is formed between the first conductive layer and the second conductive layer,

wherein the memory layer includes nanoparticles covered with the organic material.

16. The method for manufacturing a memory element according to claim 15,

wherein irradiation with the ultraviolet ray is performed using a low-pressure mercury vapor lamp.

17. The method for manufacturing a memory element according to claim 15,

wherein irradiation with the ultraviolet ray is performed using an excimer lamp.

18. The method for manufacturing a memory element according to claim 15,

wherein reduction treatment is performed after the irradiating step.

19. The method for manufacturing a memory element according to claim 15,

wherein a grain diameter of each of the nanoparticles is greater than or equal to 1 nm and less than or equal to 200 nm.

20. The method for manufacturing a memory element according to claim 15,

wherein the organic material comprises a surfactant or a substance which can form a coordinate bond with the conductive material.

21. A method for manufacturing a memory element, comprising the steps of:

forming a first conductive layer;

forming a composition layer over the first conductive layer by discharging a composition in which nanoparticles comprising a conductive material covered with an organic material are dispersed in a solvent;

drying the composition layer to vaporize the solvent;

irradiating the composition layer with an ultraviolet ray with a wavelength of less than or equal to 240 nm in the air; and

baking the composition layer so that a portion of the composition layer which is irradiated with the ultraviolet ray is made to be a second conductive layer by sintering the nanoparticles and a memory layer is formed between the first conductive layer and the second conductive layer,

wherein the memory layer includes the nanoparticles covered with the organic materials which are included in the composition.

22. The method for manufacturing a memory element according to claim 21,

wherein irradiation with the ultraviolet ray is performed using a low-pressure mercury vapor lamp.

23. The method for manufacturing a memory element according to claim 21,

wherein irradiation with the ultraviolet ray is performed using an excimer lamp.

24. The method for manufacturing a memory element according to claim 21,

wherein reduction treatment is performed after the irradiating step.

25. The method for manufacturing a memory element according to claim 21,

wherein a grain diameter of each of the nanoparticles is greater than or equal to 1 nm and less than or equal to 200 nm.

26. The method for manufacturing a memory element according to claim 21,

wherein the organic material comprises a surfactant or a substance which can form a coordinate bond with the conductive material.

27. A method for manufacturing a memory element, comprising the steps of:

forming a first conductive layer;

forming a composition layer over the first conductive layer by discharging a composition in which nanoparticles comprising a conductive material covered with an organic material are dispersed in a solvent;

drying the composition layer to vaporize the solvent;

irradiating the composition layer with an ultraviolet ray with a wavelength of less than or equal to 175 nm in the air; and

baking the composition layer so that a portion of the composition layer which is irradiated with the ultraviolet ray is made to be a second conductive layer by sintering the nanoparticles and a memory layer is formed between the first conductive layer and the second conductive layer,

wherein the memory layer includes nanoparticles covered with organic materials which are included in the composition.

28. The method for manufacturing a memory element according to claim 27,

wherein irradiation with the ultraviolet ray is performed using an excimer lamp.

29. The method for manufacturing a memory element according to claim 27,

wherein reduction treatment is performed after the irradiating step.

30. The method for manufacturing a memory element according to claim 27,

wherein a grain diameter of each of the nanoparticles is greater than or equal to 1 nm and less than or equal to 200 nm.

31. The method for manufacturing a memory element according to claim 27,

wherein the organic material comprises a surfactant or a substance which can form a coordinate bond with the conductive material.