Method of forming a MIM capacitor with metal nitride electrode

• US 6,881,642 B2
• Filed: 04/21/2003
• Issued: 04/19/2005
• Est. Priority Date: 03/11/2002
• Status: Expired due to Fees

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Basceri, Cem, Graettinger, Thomas M.
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): TRAN, LONG K
• Application Number:
  US10/419,191
• Publication Number:
  US 20030205729A1
• Time in Patent Office: 729 Days
• Field of Search: 438/386, 438/243, 438/396, 438/398, 438/244, 438/250, 438/257, 438/253, 438/379, 438/387, 438/399, 438/683, 438/685, 438/238, 438/393, 438/686, 438/267, 438/771, 257/915, 257/296, 257/298, 257300-308
• US Class Current: 438/386
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• CPC Class Codes: H01L 21/02183 the material containing tantalum, e.g. Ta2O5
• CPC Class Codes: H01L 21/02194 the material containing more than one metal element
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/28568 the conductive layers comprising transition metals H01L21/28518 takes precedence
• CPC Class Codes: H01L 21/3162 on a silicon body
• CPC Class Codes: H01L 28/75 comprising two or more layers, e.g. comprising a barrier layer and a metal layer
• CPC Class Codes: H01L 28/84 being a rough surface, e.g. using hemispherical grains
• CPC Class Codes: H01L 28/90 having vertical extensions

Abstract

A method of forming an MIM capacitor with low leakage and high capacitance is disclosed. A layer of titanium nitride (TiN) or boron-doped titanium nitride (TiBN) material is formed as a lower electrode over an optional capacitance layer of hemispherical grained polysilicon (HSG). Prior to the dielectric formation, the first layer may be optionally subjected to a nitridization or oxidation process. A dielectric layer of, for example, aluminum oxide (Al₂O₃) formed by atomic layer deposition (ALD) is fabricated over the first layer and after the optional nitridization or oxidation process. An upper electrode of titanium nitride (TiN) or boron-doped titanium nitride (TiBN) is formed over the dielectric layer.

Claims

1. A method of forming an MIM capacitor on a semiconductor substrate, comprising the acts of:

providing a conductive support layer over a polysilicon plug formed over a substrate;

providing a first metal nitride layer over said conductive support layer;

providing a dielectric layer over said first metal nitride layer and in contact with said conductive support layer; and

providing a second metal nitride layer over said dielectric layer, wherein each of said first and second metal nitride layers is formed of titanium nitride or boron-doped titanium nitride material.

2. The method of claim 1, wherein each of said first and second metal nitride layers is a titanium nitride layer.

3. The method of claim 1, wherein said conductive support layer is a layer of hemispherical grained polysilicon adjacent said first metal nitride layer.

4. The method of claim 3 further comprising the act of opening grains forming said layer of hemispherical grained polysilicon, to activate said grains.

5. The method of claim 4, wherein said act of opening said grains further comprising etching said layer of hemispherical grained polysilicon to form an etched layer of hemispherical grained polysilicon.

6. The method of claim 5, wherein said act of etching said layer of hemispherical grained polysilicon further comprises contacting said layer of hemispherical grained polysilicon with a solution of HF.

7. The method of claim 3 further comprising the act of subjecting said layer of hemispherical grained polysilicon to an RTN process.

8. The method of claim 3 further comprising the act of subjecting said layer of hemispherical grained polysilicon to an anneal process.

9. The method of claim 3 further comprising the act of subjecting said layer of hemispherical grained polysilicon to a PH₃ anneal.

10. The method of claim 1, wherein said first metal nitride layer is a titanium nitride layer formed by chemical vapor deposition.

11. The method of claim 10, wherein said titanium nitride layer is formed by chemical vapor deposition using a nitrogen source and a titanium source precursor.

12. The method of claim 11, wherein said titanium source precursor is selected from the group consisting of titanium tetrachloride, titanium trichloride, bis(cyclopentadienyl)titanium dichloride and cyclopentadienyltitanium trichloride.

13. The method of claim 1, wherein said first metal nitride layer is a titanium nitride layer formed by atomic layer deposition.

14. The method of claim 13, wherein said titanium nitride layer is formed by atomic layer deposition using a nitrogen source and a titanium source precursor.

15. The method of claim 14, wherein said titanium source precursor is selected from the group consisting of titanium tetrachloride, titanium trichloride, bis(cyclopentadienyl)titanium dichloride and cyclopentadienyltitanium trichloride.

16. The method of claim 1 further comprising the act of subjecting said first metal nitride layer to a nitridizing ambient.

17. The method of claim 16, wherein said act of subjecting said first metal nitride layer to a nitridizing ambient further comprising the act of exposing said first metal nitride layer to a nitrogen-containing plasma at a temperature from about 500°

C. to about 900°

C.

18. The method of claim 1 further comprising the act of subjecting said first metal nitride layer to an oxidizing ambient.

19. The method of claim 18, wherein said act of subjecting said first metal nitride layer to an oxidizing ambient further comprising the act of exposing said first metal nitride layer to a remote oxygen-containing plasma.

20. The method of claim 1, wherein said dielectric layer is an aluminum oxide layer.

21. The method of claim 20, wherein said aluminum oxide layer is formed by atomic layer deposition.

22. The method of claim 21, wherein said aluminum oxide layer is formed by atomic layer deposition using an oxygen source and an aluminum source precursor.

23. The method of claim 22, wherein said aluminum source precursor is aluminum tetrachloride or aluminum trichloride.

24. The method of claim 1, wherein said second metal nitride layer is a titanium nitride layer formed by chemical vapor deposition.

25. The method of claim 24, wherein said titanium nitride layer is formed by chemical vapor deposition using a nitrogen source and a titanium source precursor.

26. The method of claim 25, wherein said titanium source precursor is selected from the group consisting of titanium tetrachloride, titanium trichloride, bis(cyclopentadienyl)titanium dichloride and cyclopentadienyltitanium trichloride.

27. The method of claim 1, wherein said second metal nitride layer is a titanium nitride layer formed by atomic layer deposition.

28. The method of claim 27, wherein said titanium nitride layer is formed by atomic layer deposition using a nitrogen source and a titanium source precursor.

29. The method of claim 28, wherein said titanium source precursor is selected from the group consisting of titanium tetrachloride, titanium trichloride, bis(cyclopentadienyl)titanium dichloride and cyclopentadienyltitanium trichloride.

30. A method of forming an MIM capacitor on a semiconductor substrate, comprising the acts of:

providing a first metal nitride layer over a substrate;

providing a dielectric layer over said first metal nitride layer; and

providing a second metal nitride layer over said dielectric layer, wherein each of said first and second metal nitride layers is a boron-doped titanium nitride layer.

31. A method of forming an MIM capacitor on a semiconductor substrate, comprising the acts of:

providing a first metal nitride layer over a substrate;

providing a dielectric layer over said first metal nitride layer; and

providing a second metal nitride layer over said dielectric layer, wherein said first metal nitride layer is a titanium nitride layer and said second metal nitride layer is a boron-doped titanium nitride layer.

32. A method of forming an MIM capacitor on a semiconductor substrate, comprising the acts of:

providing a first metal nitride layer over a substrate;

providing a dielectric layer over said first metal nitride layer; and

providing a second metal nitride layer over said dielectric layer, wherein said first metal nitride layer is a boron-doped titanium nitride layer and said second metal nitride layer is a titanium nitride layer.

33. A method of forming an MIM capacitor on a semiconductor substrate, comprising the acts of:

providing a first metal nitride layer over a substrate wherein said first metal nitride layer is a boron-doped titanium nitride layer formed by chemical vapor deposition;

providing a dielectric layer over said first metal nitride layer; and

providing a second metal nitride layer over said dielectric layer.

34. The method of claim 33, wherein said act of providing said boron-doped titanium nitride layer further comprises the act of incorporating boron into a titanium nitride layer.

35. The method of claim 34, wherein said act of incorporating boron into a titanium nitride layer further comprises the act of exposing said titanium nitride layer to B₂H₆.

36. The method of claim 35, wherein said act of incorporating boron into a titanium nitride layer further comprises the act of exposing said titanium nitride layer to B₂H₆ at a temperature of about 200°

C. to about 600°

C.

37. The method of claim 35 further comprising the act of exposing said titanium nitride layer and B₂H₆ to ultraviolet light.

38. A method of forming an MIM capacitor on a semiconductor substrate, comprising the acts of:

providing a first metal nitride layer over a substrate;

providing a dielectric layer over said first metal nitride layer; and

providing a second metal nitride layer over said dielectric layer, wherein said second metal nitride layer is a boron-doped titanium nitride layer formed by chemical vapor deposition.

39. The method of claim 38, wherein said act of providing said boron-doped titanium nitride layer further comprises the act of incorporating boron into a titanium nitride layer.

40. The method of claim 39, wherein said act of incorporating boron into a titanium nitride layer further comprises the act of exposing said titanium nitride layer to B₂H₆.

41. The method of claim 40, wherein said act of incorporating boron into a titanium nitride layer further comprises the act of exposing said titanium nitride layer to B₂H₆ at a temperature of about 200°

C. to about 600°

C.

42. The method of claim 40 further comprising the act of exposing said titanium nitride layer and B₂H₆ to ultraviolet light.

43. A method of forming an aluminum oxide MIM capacitor on a semiconductor substrate, comprising the acts of:

providing a layer of hemispherical grained polysilicon over a semiconductor substrate;

etching said layer of hemispherical grained polysilicon to form an etched layer of hemispherical grained polysilicon;

forming a lower capacitor electrode of titanium nitride or boron-doped titanium nitride material over said etched layer of hemispherical grained polysilicon;

forming an aluminum oxide dielectric layer by atomic layer deposition in contact with said lower capacitor electrode; and

forming an upper capacitor electrode of titanium nitride or boron-doped titanium nitride material in contact with said aluminum oxide dielectric layer.

44. The method of claim 43, wherein each of said lower and upper electrodes is a titanium nitride layer formed by atomic layer deposition.

45. The method of claim 44, wherein said titanium nitride layer is formed by atomic layer deposition using a nitrogen source and a titanium source precursor.

46. The method of claim 45, wherein said titanium source precursor is selected from the group consisting of titanium tetrachloride, titanium trichloride, bis(cyclopentadienyl)titanium dichloride and cyclopentadienyltitanium trichloride.

47. The method of claim 43, wherein said act of etching said layer of hemispherical grained polysilicon further comprises contacting said layer of hemispherical grained polysilicon with a solution of HF.

48. The method of claim 47 further comprising the act of subjecting said layer of hemispherical grained polysilicon to an RTN process.

49. The method of claim 48 further comprising the act of subjecting said layer of hemispherical grained polysilicon to an anneal process.

50. The method of claim 49 further comprising the act of subjecting said layer of hemispherical grained polysilicon to a PH₃ anneal.

51. A method of forming an aluminum oxide MIM capacitor on a semiconductor substrate, comprising the acts of:

forming a lower capacitor electrode over said semiconductor substrate;

forming an aluminum oxide dielectric layer by atomic layer deposition over said lower capacitor electrode; and

forming an upper capacitor electrode over said aluminum oxide dielectric layer, wherein each of said lower and upper electrodes is a boron-doped titanium nitride layer formed by chemical vapor deposition.

52. A method of forming an aluminum oxide MIM capacitor on a semiconductor substrate, comprising the acts of:

forming a lower capacitor electrode over said semiconductor substrate;

forming an aluminum oxide dielectric layer by atomic layer deposition over said lower capacitor electrode; and

forming an upper capacitor electrode over said aluminum oxide dielectric layer, wherein each of said lower and upper electrodes is a boron-doped titanium nitride layer formed by incorporating boron into a titanium nitride layer.

53. The method of claim 52, wherein said act of incorporating boron into said titanium nitride layer further comprises the act of exposing said titanium nitride layer to B₂H₆.

54. The method of claim 53, wherein said act of incorporating boron into a titanium nitride layer further comprises the act of exposing said titanium nitride layer to B₂H₆ at a temperature of about 200°

C. to about 600°

C.

55. The method of claim 54 further comprising the act of exposing said titanium nitride layer and B₂H₆ to ultraviolet light.