PHASE CHANGE MEMORY DEVICE AND METHOD FOR FABRICATING THE SAME

• US 20080164504A1
• Filed: 09/18/2007
• Published: 07/10/2008
• Est. Priority Date: 01/10/2007
• Status: Active Grant

• Current Assignee: Nanya Technology Corporation, ProMOS Technologies, Inc., Winbond Electronics Corporation
• Original Assignee: Industrial Technology Research Institute, Nanya Technology Corporation, Powerchip Semiconductor Corporation (Powerchip Technology Corporation), ProMOS Technologies, Inc., Winbond Electronics Corporation
• Inventors: Lee, Chien-Min, Chen, Wei-Su, Hsu, Hong-Hui, Chen, Chih-Wei, Chen, Yi-Chan, Tsai, Ming-Jinn, Chao, Der-Sheng
• Granted Patent: US 7,989,795 B2
• Time in Patent Office: Days
• US Class Current: 257/296
• CPC Class Codes: H10B 63/20 comprising selection components having two electrodes, e.g. diodes
• 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: H10N 70/068 by processes specially adapted for achieving sub-lithographic dimensions, e.g. using spacers
• 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 70/8265 on sidewalls of dielectric structures, e.g. mesa or cup type devices
• CPC Class Codes: H10N 70/8413 adapted for resistive heating
• CPC Class Codes: H10N 70/8828 Tellurides, e.g. GeSbTe
• CPC Class Codes: H10N 70/884 Other compounds of groups 13-15, e.g. elemental or compound semiconductors

Abstract

A phase change memory device is provided. The phase change memory device comprises a substrate. An electrode layer is on the substrate. A phase change memory structure is on the electrode layer and electrically connected to the electrode layer, wherein the phase change memory structure comprises a cup-shaped heating electrode on the electrode layer. An insulating layer is on the cup-shaped heating electrode along a first direction covering a portion of the cup-shaped heating electrode. An electrode structure is on the cup-shaped heating electrode along a second direction covering a portion of the insulating layer and the cup-shaped heating electrode. A pair of double spacers is on a pair of sidewalls of the electrode structure covering a portion of the cup-shaped heating electrode, wherein the double spacer comprises a phase change material spacer and an insulating material spacer on a sidewall of the phase change material spacer.

Claims

1. A phase change memory device, comprising:

a substrate;

an electrode layer formed on the substrate;

a phase change memory structure formed on the electrode layer and electrically connected to the electrode layer, wherein the phase change memory structure comprises;

a cup-shaped heating electrode placed on the electrode layer;

an insulating layer placed on the cup-shaped heating electrode along a first direction covering a portion of the cup-shaped heating electrode;

an electrode structure placed on the cup-shaped heating electrode along a second direction covering a portion of the insulating layer and the cup-shaped heating electrode;

a pair of double spacers placed on a pair of sidewalls of the electrode structure covering a portion of the cup-shaped heating electrode, wherein the double spacer comprises a phase change material spacer and an insulating material spacer placed on a sidewall of the phase change material spacer.

2. The phase change memory device as claimed in claim 1, the cup-shaped heating electrode further comprising:

a switching element;

a conductive layer placed on the switch element and electrically connected to the switching element, wherein the conductive layer is cup-shaped with a cup-shaped opening; and

an insulating layer placed on the conductive layer and filled in the cup-shaped opening.

3. The phase change memory device as claimed in claim 2, wherein the switching element comprises a diode structure or an interconnect structure.

4. The phase change memory device as claimed in claim 2, wherein the conductive layer comprises metals, alloys, metal compounds, semiconductor materials or combinations thereof.

5. The phase change memory device as claimed in claim 4, wherein the metal comprises aluminum (Al), copper (Cu), cobalt (Co), tantalum (Ta), nickel (Ni), titanium (Ti), tungsten (W) or combinations thereof.

6. The phase change memory device as claimed in claim 4, wherein the alloy comprises aluminum-alloy, copper-alloy, cobalt-alloy, tantalum-alloy, nickel-alloy, titanium-alloy, tungsten-alloy, TiW, GaSb, GeTe, Ge₂Sb₂Te₅, Ag—

In—

Sb—

Te or combinations thereof.

7. The phase change memory device as claimed in claim 4, wherein the metal compound comprises CoN, TaN, NiN, TiN, WN, CoSi_mN_n, TaSi_mN_n, NiSi_mN_n, TiSi_mN_n, WSi_mN_n, Co-salicide (CoSi_z), Ta-salicide (TaSi_z), Ni-salicide (NiSi_z), Ti-salicide (TiSi_z), W-salicide (WSi_z), yttrium barium copper oxide (YBCO), Cu₂O, indium tin oxide (ITO) or combinations thereof.

8. The phase change memory device as claimed in claim 4, wherein the semiconductor material comprises polycrystalline semiconductor material, amorphous semiconductor material or combinations thereof.

9. The phase change memory device as claimed in claim 1, wherein the conductive layer has a square-ring shape from a top view.

10. The phase change memory device as claimed in claim 1, wherein the insulating layer covers one half of the cup-shaped heating electrode.

11. The phase change memory device as claimed in claim 1, wherein the electrode structure covers one quarter of the cup-shaped heating electrode.

12. The phase change memory device as claimed in claim 1, wherein the electrode structure is a composite layer comprising an insulating layer and a conductive layer.

13. The phase change memory device as claimed in claim 12, wherein the conductive layer comprises metals, alloys, metal compounds, semiconductor materials or combinations thereof.

14. The phase change memory device as claimed in claim 13, wherein the metal comprises aluminum (Al), copper (Cu), cobalt (Co), tantalum (Ta), nickel (Ni), titanium (Ti), tungsten (W) or combinations thereof.

15. The phase change memory device as claimed in claim 13, wherein the alloy comprises aluminum-alloy, copper-alloy, cobalt-alloy, tantalum-alloy, nickel-alloy, titanium-alloy, tungsten-alloy, TiW, GaSb, GeTe, Ge₂Sb₂Te₅, Ag—

In—

Sb—

Te alloy or combinations thereof.

16. The phase change memory device as claimed in claim 13, wherein the metal compound comprises CoN, TaN, NiN, TiN, WN, CoSi_mN_n, TaSi_mN_n, NiSi_mN_n, TiSi_mN_n, WSi_mN_n, Co-salicide (CoSi_z), Ta-salicide (TaSi_z), Ni-salicide (NiSi_z), Ti-salicide (TiSi_z), W-salicide (WSi_z), yttrium barium copper oxide (YBCO), Cu₂O, indium tin oxide (ITO) or combinations thereof.

17. The phase change memory device as claimed in claim 13, wherein the semiconductor material comprises polycrystalline semiconductor material, amorphous semiconductor material or combinations thereof.

18. The phase change memory device as claimed in claim 13, wherein the conductive layer comprises a single layer or stacked layers.

19. The phase change memory device as claimed in claim 1, wherein the first direction is substantially perpendicular to the second direction.

20. The phase change memory device as claimed in claim 1, wherein the phase change material spacer and the insulating material spacer have an etching selectivity of about 1 to 1000.

21. The phase change memory device as claimed in claim 1, further comprising:

another phase change material structure stacked on the phase change material structure vertically and electrically connected each other.

22. A method of fabricating a phase change memory device, comprising:

providing a substrate with an electrode layer formed thereon;

forming a phase change memory structure on the electrode layer and electrically connected to the electrode layer, wherein the phase change memory structure comprises;

forming a cup-shaped heating electrode on the electrode layer;

forming an insulating layer on the cup-shaped heating electrode along a first direction and covering a portion of the cup-shaped heating electrode;

forming an electrode structure along a second direction and covering a portion of the insulating layer and the cup-shaped heating electrode; and

forming a pair of double spacers on a pair of sidewalls of the electrode structure and covering a portion of the cup-shaped heating electrode, wherein the double spacer comprises a phase change material spacer and an insulating material spacer placed on a sidewall of the phase change material spacer.

23. The method of fabricating the phase change memory device as claimed in claim 22, further comprising:

forming a switching element on the electrode layer and electrically connected to the electrode layer; and

forming a dielectric layer on the electrode layer and the switching element and covering the switching element.

24. The method of fabricating the phase change memory device as claimed in claim 23, wherein the switching element comprises a diode structure or an interconnect structure.

25. The method of fabricating the phase change memory device as claimed in claim 23, further comprising:

forming a plurality of hard masking layers on the dielectric layer, wherein sidewalls of the plurality of hard masking layers is separated from a set of sidewalls of the switching element by a first distance;

forming a plurality of photoresist layers on and substantially perpendicular to the plurality of hard masking layers, wherein sidewalls of the plurality of photoresist layers is separated from another set of sidewalls of the switching element by a second distance;

removing a portion of the dielectric layer until the switching element is exposed to form a cup-shaped opening using the plurality of hard masking layers and photoresist layers as etching hard masks;

forming a conductive layer in the cup-shaped opening, wherein the conductive layer is cup-shaped;

forming an insulating layer on the conductive layer and filling the insulating layer into the cup-shaped opening; and

performing a planarizing process to remove a portion of the conductive layer and the insulating layer to form the cup-shaped heating electrode.

26. The method of fabricating the phase change memory device as claimed in claim 25, wherein the first distance is equal to the second distance.

27. The method of fabricating the phase change memory device as claimed in claim 25, wherein the first distance is different from the second distance.

28. The method of fabricating the phase change memory device as claimed in claim 22, wherein the insulating layer covers half the cup-shaped heating electrode.

29. The method of fabricating the phase change memory device as claimed in claim 22, wherein the electrode structure covers quarter of the cup-shaped heating electrode.

30. The method of fabricating the phase change memory device as claimed in claim 22, further comprising:

forming a stacked structure comprising an insulating layer and a conductive layer on the cup-shaped heating electrode;

sequentially forming a phase change material layer and an insulating material layer on the stacked structure;

removing a portion of insulating material layer to form a pair of insulating material spacers above sidewalls of the stacked structure; and

removing a portion of the phase change material layer using the pair of insulating material spacers as masks to form a pair of phase change material spacers on sidewalls of the stacked structure to form the electrode structure.

31. A phase change memory device, comprising:

a substrate;

an electrode layer formed on the substrate;

a dielectric layer formed on the electrode layer;

a phase change memory structure formed in the dielectric layer and electrically connected to the electrode layer, wherein the phase change memory structure comprises;

a cup-shaped heating electrode placed in a cup-shaped opening in the dielectric layer, wherein the cup-shaped heating electrode comprises a conductive layer covering a portion of a sidewall of the cup-shaped heating electrode;

an electrode structure placed on the cup-shaped heating electrode and covering a portion of the cup-shaped heating electrode;

a pair of double spacers placed on a pair of sidewalls of the electrode structure and covering a portion of the cup-shaped heating electrode, wherein the double spacer comprises a phase change material spacer and an insulating material spacer placed on a sidewall of the phase change material spacer.

32. The phase change memory device as claimed in claim 31, the cup-shaped heating electrode further comprising:

a switching element placed under the conductive layer and electrically connected to the conductive layer; and

an insulating layer placed on the conductive layer and filled in the cup-shaped opening, wherein the insulating layer covers a portion of the sidewall of the cup-shaped opening.

33. The phase change memory device as claimed in claim 32, wherein the switching element comprises a diode structure or an interconnect structure.

34. The phase change memory device as claimed in claim 31, wherein the conductive layer comprises metals, alloys, metal compounds, semiconductor materials or combinations thereof.

35. The phase change memory device as claimed in claim 34, wherein the metal comprises aluminum (Al), copper (Cu), cobalt (Co), tantalum (Ta), nickel (Ni), titanium (Ti), tungsten (W) or combinations thereof.

36. The phase change memory device as claimed in claim 34, wherein the alloy comprises aluminum-alloy, copper-alloy, cobalt-alloy, tantalum-alloy, nickel-alloy, titanium-alloy, tungsten-alloy, TiW, GaSb, GeTe, Ge₂Sb₂Te₅, Ag—

In—

Sb—

Te or combinations thereof.

37. The phase change memory device as claimed in claim 34, wherein the metal compound comprises CoN, TaN, NiN, TiN, WN, CoSi_mN_n, TaSi_mN_n, NiSi_mN_n, TiSi_mN_n, WSi_mN_n, Co-salicide (CoSi_z), Ta-salicide (TaSi_z), Ni-salicide (NiSi_z), Ti-salicide (TiSi_z), W-salicide (WSi_z), yttrium barium copper oxide (YBCO), Cu₂O, indium tin oxide (ITO) or combinations thereof.

38. The phase change memory device as claimed in claim 34, wherein the semiconductor material comprises polycrystalline semiconductor material, amorphous semiconductor material or combinations thereof.

39. The phase change memory device as claimed in claim 31, wherein the conductive layer is U-shaped from a top view.

40. The phase change memory device as claimed in claim 31, wherein the electrode structure covers half the cup-shaped heating electrode.

41. The phase change memory device as claimed in claim 31, wherein the electrode structure is a composite layer comprising an insulating layer and a conductive layer.

42. The phase change memory device as claimed in claim 41, wherein the conductive layer comprises metals, alloys, metal compounds, semiconductor materials or combinations thereof.

43. The phase change memory device as claimed in claim 42, wherein the metal comprises aluminum (Al), copper (Cu), cobalt (Co), tantalum (Ta), nickel (Ni), titanium (Ti), tungsten (W) or combinations thereof.

44. The phase change memory device as claimed in claim 42, wherein the alloy comprises aluminum-alloy, copper-alloy, cobalt-alloy, tantalum-alloy, nickel-alloy, titanium-alloy, tungsten-alloy, TiW, GaSb, GeTe, Ge₂Sb₂Te₅, Ag—

In—

Sb—

Te alloy or combinations thereof.

45. The phase change memory device as claimed in claim 42, wherein the metal compound comprises CoN, TaN, NiN, TiN, WN, COSi_mN_n, TaSi_mN_n, NiSi_mN_n, TiSi_mN_n, WSi_mN_n, Co-salicide (CoSi_z), Ta-salicide (TaSi_z), Ni-salicide (NiSi_z), Ti-salicide (TiSi_z), W-salicide (WSi_z), yttrium barium copper oxide (YBCO), Cu₂O, indium tin oxide (ITO) or combinations thereof.

46. The phase change memory device as claimed in claim 42, wherein the semiconductor material comprises polycrystalline semiconductor material, amorphous semiconductor material or combinations thereof.

47. The phase change memory device as claimed in claim 42, wherein the conductive layer comprises a single layer or stacked layers.

48. The phase change memory device as claimed in claim 31, wherein the phase change material spacer and the insulating material spacer have an etching selectivity of about 1 to 1000.

49. The phase change memory device as claimed in claim 41, further comprising:

another phase change material structure stacked vertically on and electrically connected to the phase change material structure.

50. A method of fabricating a phase change memory device, comprising:

providing a substrate with an electrode layer formed thereon;

forming a dielectric layer on the electrode layer;

forming a phase change memory structure in the dielectric layer and electrically connected to the electrode layer, wherein the phase change memory structure comprises;

forming a cup-shaped heating electrode in a cup-shaped opening in the dielectric layer, wherein the cup-shaped heating electrode comprises a conductive layer covering a portion of a sidewall of the cup-shaped heating electrode;

forming an electrode structure on the cup-shaped heating electrode covering a portion of the cup-shaped heating electrode; and

forming a pair of double spacers on a pair of sidewalls of the electrode structure and covering a portion of the cup-shaped heating electrode, wherein the double spacer comprises a phase change material spacer and an insulating material spacer placed on a sidewall of the phase change material spacer.

51. The method of fabricating the phase change memory device as claimed in claim 50, further comprising:

forming a switching element on the electrode layer and electrically connected to the electrode layer; and

forming a dielectric layer on the electrode layer and the switching element and covering the switching element.

52. The method of fabricating the phase change memory device as claimed in claim 51, wherein the switching element comprises a diode structure or an interconnect structure.

53. The method of fabricating the phase change memory device as claimed in claim 50, further comprising:

forming a plurality of hard masking layers on the dielectric layer, wherein sidewalls of the plurality of hard masking layers is separated from a set of sidewalls of the switching element by a first distance;

forming a plurality of photoresist layers on and substantially perpendicular to the plurality of hard masking layers, wherein sidewalls of the plurality of photoresist layers is separated from another set of sidewalls of the switching element by a second distance;

removing a portion of the dielectric layer until the switching element is exposed to form a cup-shaped opening using the plurality of hard masking layers and photoresist layers as etching hard masks;

forming a conductive layer in the cup-shaped opening, wherein the conductive layer is cup-shaped;

forming an insulating layer on the conductive layer and filling the insulating layer into the cup-shaped opening; and

performing a planarizing process to remove a portion of the conductive layer and the insulating layer to form the cup-shaped heating electrode.

54. The method of fabricating the phase change memory device as claimed in claim 53, wherein the first distance is equal to the second distance.

55. The method of fabricating the phase change memory device as claimed in claim 53, wherein the first distance is different from the second distance.

56. The method of fabricating the phase change memory device as claimed in claim 50, further comprising:

removing a portion of the conductive layer and the insulating layer in the cup-shaped opening to form another opening by photolithography and etching processes; and

filling another insulating layer and covering on the insulating layer.

57. The method of fabricating the phase change memory device as claimed in claim 56, wherein a mask used for forming the other opening is the same as a mask used for forming the plurality of photoresist layers.

58. The method of fabricating the phase change memory device as claimed in claim 50, wherein the electrode structure covers half the cup-shaped heating electrode.

59. The method of fabricating the phase change memory device as claimed in claim 50, further comprising:

forming a stacked structure comprising an insulating layer and a conductive layer on the cup-shaped heating electrode;

sequentially forming a phase change material layer and an insulating material layer on the stacked structure;

removing a portion of insulating material layer to form a pair of insulating material spacers above sidewalls of the stacked structure; and

removing a portion of the phase change material layer using the pair of insulating material spacers as masks to form a pair of phase change material spacers on sidewalls of the stacked structure to form the electrode structure.