Atomic layer deposited dielectric layers

• US 7,192,892 B2
• Filed: 03/04/2003
• Issued: 03/20/2007
• Est. Priority Date: 03/04/2003
• Status: Expired due to Fees

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Ahn, Kie Y., Forbes, Leonard
• Primary Examiner(s): SMITH, BRADLEY
• Application Number:
  US10/379,470
• Publication Number:
  US 20040175882A1
• Time in Patent Office: 1,477 Days
• Field of Search: 438/240, 438/778, 438/591, 438/253, 438/216, 438/149, 438/151, 438/142, 438/197, 438/238, 438/239, 438/584, 438/585, 438/758, 438/785, 257/E21.461
• US Class Current: 438/785
• CPC Class Codes: H01L 21/02175 characterised by the metal H01L21/02197 takes precedence
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/28229 by deposition of a layer, e.g. metal, metal compound or poysilicon, followed by transformation thereof into an insulating layer
• CPC Class Codes: H01L 21/3141 Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/31645 Deposition of Hafnium oxides, e.g. HfO2
• CPC Class Codes: H01L 21/31683 of metallic layers, e.g. Al deposited on the body, e.g. formation of multi-layer insulating structures
• CPC Class Codes: H01L 28/40 Capacitors
• CPC Class Codes: H01L 29/40114 the electrodes comprising a conductor-insulator-conductor-insulator-semiconductor structure
• CPC Class Codes: H01L 29/517 the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• CPC Class Codes: H01L 29/66825 with a floating gate H01L29/6684 takes precedence
• CPC Class Codes: H01L 29/78 with field effect produced by an insulated gate H01L29/7725, H01L29/775, H01L29/778 take precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H10B 10/00 Static random access memory [SRAM] devices
• CPC Class Codes: H10B 12/05 Making the transistor

Abstract

An atomic layer deposited dielectric layer and a method of fabricating such a dielectric layer produce a reliable dielectric layer having an equivalent oxide thickness thinner than attainable using SiO₂. Depositing a hafnium metal layer on a substrate surface by atomic layer deposition and depositing a hafnium oxide layer on the hafnium metal layer by atomic layer deposition form a hafnium oxide dielectric layer substantially free of silicon oxide. Dielectric layers containing atomic layer deposited hafnium oxide are thermodynamically stable such that the hafnium oxide will have minimal reactions with a silicon substrate or other structures during processing.

Claims

1. A method of forming a dielectric layer comprising:

forming a layer of a metal on a substrate by atomic layer deposition; and

forming on the metal, by another atomic layer deposition, an oxide of the metal, wherein, as the oxide is being formed, oxygen diffuses into the layer of the metal such that essentially the layer of the metal completely becomes a metal oxide.

2. The method of claim 1, wherein forming a layer of a metal on a substrate by atomic layer deposition includes performing a predetermined number of atomic layer deposition cycles to deposit the layer of metal on the substrate, prior to forming the oxide of the metal.

3. The method of claim 2, wherein performing a predetermined number of atomic layer deposition cycles includes performing at most ten cycles.

4. The method of claim 2, wherein performing a predetermined number of atomic layer deposition cycles includes performing a number of cycles ranging from 4 to 10 cycles.

5. A method of forming a dielectric layer comprising:

forming a layer of hafnium on a substrate by atomic layer deposition; and

forming a layer of hafnium oxide on the layer of hafnium by another atomic layer deposition, wherein, as the hafnium oxide is being formed, oxygen diffuses into the layer of the hafnium such that essentially the layer of hafnium completely becomes hafnium oxide.

6. The method of claim 5, wherein forming a layer of hafnium on a substrate by atomic layer deposition includes pulsing a hafnium nitrate precursor on the substrate.

7. The method of claim 5, wherein forming a layer of hafnium on a substrate by atomic layer deposition includes pulsing an anhydrous hafnium nitrate precursor on the substrate.

8. The method of claim 5, wherein forming a layer of hafnium on a substrate by atomic layer deposition includes performing at most ten atomic layer deposition cycles to deposit the layer of hafnium on the substrate.

9. The method of claim 5, wherein forming a layer of hafnium on a substrate by atomic layer deposition includes performing a number of atomic layer deposition cycles ranging from 4 to 10 cycles to deposit the layer of hafnium on the substrate.

10. The method of claim 5, wherein forming a layer of hafnium oxide on the layer of hafnium by atomic layer deposition includes performing an atomic layer deposition cycle using an anhydrous hafnium nitrate precursor and a water vapor precursor.

11. The method of claim 5, wherein the method further includes maintaining the substrate at about 180°

C. during the forming of the layer of hafnium and the forming of the layer of hafnium oxide.

12. A method of forming a capacitor, comprising:

forming a first conductive layer on a substrate;

forming a layer of a metal on the first conductive layer by atomic layer deposition;

forming a layer of an oxide of the metal on the layer of metal by another atomic layer deposition, wherein, as the oxide is being formed, oxygen diffuses into the layer of the metal such that essentially the layer of the metal completely becomes a metal oxide; and

forming a second conductive layer on the layer of the oxide of the metal layer.

13. The method of claim 12, wherein forming a layer of a metal on the first conductive layer by atomic layer deposition includes performing at most ten atomic layer deposition cycles to deposit the layer of the metal.

14. The method of claim 12, wherein forming a layer of an oxide of the metal on the layer of metal by atomic layer deposition includes performing an atomic layer deposition cycle using an anhydrous hafnium nitrate precursor and a water vapor precursor.

15. The method of claim 12, wherein forming a layer of a metal on the first conductive layer by atomic layer deposition includes forming a layer of hafnium on the first conductive layer by atomic layer deposition.

16. The method of claim 15, wherein forming a layer of hafnium on the first conductive layer by atomic layer deposition includes pulsing a hafnium nitrate precursor.

17. The method of claim 15, wherein forming a layer of hafnium on the first conductive layer by atomic layer deposition includes performing at most ten atomic layer deposition cycles to deposit the layer of hafnium.

18. The method of claim 15, wherein forming a layer of hafnium on the first conductive layer by atomic layer deposition includes performing a number of atomic layer deposition cycles ranging from 4 to 10 cycles to deposit the layer of hafnium.

19. The method of claim 15, wherein forming a layer of an oxide of the metal on the layer of metal by atomic layer deposition includes performing an atomic layer deposition cycle using an anhydrous hafnium nitrate precursor and a water vapor precursor.

20. The method of claim 15, wherein the method further includes maintaining the substrate at about 180°

C. during the forming of the layer of hafnium and the forming of the layer of hafnium oxide.

21. A method of forming a transistor comprising:

forming a source region and a drain region in a substrate, the source region and the drain region separated by a body region;

forming a dielectric layer on the body region between the source and drain regions by atomic layer deposition; and

coupling a gate to the dielectric layer, wherein forming the dielectric layer includes;

forming a layer of a metal on the body region by atomic layer deposition; and

forming a layer of an oxide of the metal on the layer of metal by another atomic layer deposition, wherein, as the oxide is being formed, oxygen diffuses into the layer of the metal such that essentially the layer of the metal completely becomes a metal oxide.

22. The method of claim 21, wherein forming a layer of a metal on the body region by atomic layer deposition includes performing at most ten atomic layer deposition cycles to deposit the layer of the metal on the body region.

23. The method of claim 21, wherein forming a layer of an oxide of the metal on the layer of metal by atomic layer deposition includes performing an atomic layer deposition cycle using an anhydrous hafnium nitrate precursor and a water vapor precursor.

24. The method of claim 21, wherein forming a layer of a metal on the body region by atomic layer deposition includes forming a layer of hafnium on the body region by atomic layer deposition.

25. The method of claim 24, wherein forming a layer of hafnium on the body region by atomic layer deposition includes pulsing a hafnium nitrate precursor.

26. The method of claim 24, wherein forming a layer of hafnium on the body region by atomic layer deposition includes performing at most ten atomic layer deposition cycles to deposit the layer of hafnium on the body region.

27. The method of claim 24, wherein forming a layer of hafnium on the body region by atomic layer deposition includes performing a number of atomic layer deposition cycles ranging from 4 to 10 cycles to deposit the layer of hafnium on the body region.

28. The method of claim 24, wherein forming a layer of an oxide of the metal on the layer of metal by atomic layer deposition includes performing an atomic layer deposition cycle using an anhydrous hafnium nitrate precursor and a water vapor precursor.

29. The method of claim 24, wherein the method further includes maintaining the substrate at about 180°

C. during the forming of the layer of hafnium and the forming of the layer of hafnium oxide.

30. A method of forming a memory comprising:

forming a number of access transistors, forming at least one of the access transistors including forming a dielectric layer on a body region between a source region and a drain region;

forming a number of word lines coupled to the number of access transistors;

forming a number of bit lines coupled to the number of access transistors, wherein forming the dielectric layer includes;

forming a layer of a metal on the body region by atomic layer deposition; and

forming a layer of an oxide of the metal on the layer of metal by another atomic layer deposition, wherein, as the oxide is being formed, oxygen diffuses into the layer of the metal such that essentially the layer of the metal completely becomes a metal oxide.

31. The method of claim 30, wherein forming a layer of a metal on the body region by atomic layer deposition includes performing at most ten atomic layer deposition cycles to deposit the layer of the metal on the body region.

32. The method of claim 30, wherein forming a layer of an oxide of the metal on the layer of metal by atomic layer deposition includes performing an atomic layer deposition cycle using an anhydrous hafnium nitrate precursor and a water vapor precursor.

33. The method of claim 30, wherein forming a layer of a metal on the body region by atomic layer deposition includes forming a layer of hafnium on the body region by atomic layer deposition.

34. The method of claim 33, wherein forming a layer of hafnium on the body region by atomic layer deposition includes pulsing a hafnium nitrate precursor.

35. The method of claim 33, wherein forming a layer of hafnium on the body region by atomic layer deposition includes performing at most ten atomic layer deposition cycles to deposit the layer of hafnium on the body region.

36. The method of claim 33, wherein forming a layer of hafnium on the body region by atomic layer deposition includes performing a number of atomic layer deposition cycles ranging from 4 to 10 cycles to deposit the layer of hafnium on the body region.

37. The method of claim 33, wherein forming a layer of an oxide of the metal on the layer of metal by atomic layer deposition includes performing an atomic layer deposition cycle using an anhydrous hafnium nitrate precursor and a water vapor precursor to form a layer of hafnium oxide.

38. The method of claim 33, wherein the method further includes maintaining the substrate at about 180°

C. during the forming of the layer of hafnium and the forming of the layer of hafnium oxide.

39. A method of forming an electronic system comprising:

providing a processor;

coupling a memory to the processor, wherein the memory is formed by a method including;

forming a number of access transistors, forming at least one of the access transistors including forming a dielectric layer on a body region between a source region and a drain region;

forming a number of word lines coupled to number of access transistors;

forming a number of bit lines coupled to the number of access transistors, wherein forming the dielectric layer includes;

forming a layer of metal on the body region by atomic layer deposition; and

forming a layer of an oxide of the metal on the layer of metal by another atomic layer deposition, wherein, as the oxide is being formed, oxygen diffuses into the layer of the metal such that essentially the layer of the metal completely becomes a metal oxide.

40. The method of claim 39, wherein forming a layer of a metal on the body region by atomic layer deposition includes performing at most ten atomic layer deposition cycles to deposit the layer of the metal on the body region.

41. The method of claim 39, wherein forming a layer of an oxide of the metal on the layer of metal by atomic layer deposition includes performing an atomic layer deposition cycle using an anhydrous hafnium nitrate precursor and a water vapor precursor.

42. The method of claim 39, wherein forming a layer of a metal on the body region by atomic layer deposition includes forming a layer of hafnium on the body region by atomic layer deposition.

43. The method of claim 42, wherein forming a layer of hafnium on the body region by atomic layer deposition includes pulsing a hafnium nitrate precursor.

44. The method of claim 42, wherein forming a layer of hafnium on the body region by atomic layer deposition includes performing at most ten atomic layer deposition cycles to deposit the layer of hafnium on the body region.

45. The method of claim 42, wherein forming a layer of hafnium on the body region by atomic layer deposition includes performing a number of atomic layer deposition cycles ranging from 4 to 10 cycles to deposit the layer of hafnium on the body region.

46. The method of claim 42, wherein forming a layer of an oxide of the metal on the layer of metal by atomic layer deposition includes performing an atomic layer deposition cycle using an anhydrous hafnium nitrate precursor and a water vapor precursor.

47. The method of claim 42, wherein the method further includes maintaining the substrate at about 180°

C. during the forming of the layer of hafnium.

48. A method of forming a transistor comprising:

forming a source region and a drain region in a substrate, the source region and the drain region separated by a body region;

forming a dielectric layer on the body region between the source and drain regions by atomic layer deposition; and

coupling a gate to the dielectric layer, wherein forming the dielectric layer includes;

forming a layer of a metal on the body region by atomic layer deposition; and

forming a layer of an oxide of the metal on the layer of metal by another atomic layer deposition, wherein, as the oxide is being formed, oxygen diffuses into the layer of the metal such that essentially the layer of metal completely becomes an oxide layer substantially preventing oxygen from diffusing to the body region.

49. The method of claim 48, wherein forming a layer of an oxide of the metal includes forming a layer of hafnium oxide.

50. The method of claim 48, wherein forming a layer of a metal includes forming a layer of hafnium on a silicon body region by atomic layer deposition.

51. A method of forming a memory comprising:

forming a number of access transistors, forming at least one of the access transistors including forming a dielectric layer on a body region between a source region and a drain region;

forming a number of word lines coupled to the number of access transistors;

forming a number of bit lines coupled to the number of access transistors, wherein forming the dielectric layer includes;

forming a layer of a metal on the body region by atomic layer deposition; and

forming a layer of an oxide of the metal on the layer of metal by another atomic layer deposition, wherein, as the oxide is being formed, oxygen diffuses into the layer of the metal such that essentially the layer of metal completely becomes an oxide layer substantially preventing oxygen from diffusing to the body region.

52. The method of claim 51, wherein forming a layer of a metal on the body region includes forming a layer of hafnium on a silicon body region by atomic layer deposition.

53. The method of claim 51, wherein forming a layer of an oxide of the metal includes forming a layer of hafnium oxide by atomic layer deposition.

54. A method of forming an electronic system comprising:

providing a processor;

coupling a memory to the processor, wherein the memory is formed by a method including;

forming a number of access transistors, forming at least one of the access transistors including forming a dielectric layer on a body region between a source region and a drain region;

forming a number of word lines coupled to number of access transistors;

forming a number of bit lines coupled to the number of access transistors, wherein forming the dielectric layer includes;

forming a layer of metal on the body region by atomic layer deposition; and

forming a layer of an oxide of the metal on the layer of metal by another atomic layer deposition, wherein, as the oxide is being formed, oxygen diffuses into the layer of the metal such that essentially the layer of metal completely becomes an oxide layer substantially preventing oxygen from diffusing to the body region.

55. The method of claim 54, wherein forming a layer of a metal on the body region by atomic layer deposition includes forming a layer of hafnium on the body region by atomic layer deposition.

56. The method of claim 54, wherein forming a layer of metal on the body region by atomic layer deposition and forming a layer of an oxide of the metal on the layer of metal by atomic layer deposition, wherein the layer of metal becomes an oxide layer includes forming a layer of hafnium on the body region by atomic layer deposition and forming a layer of hafnium oxide on the layer of hafnium by atomic layer deposition, wherein the layer of hafnium becomes a layer of hafnium oxide.