Ion sources, systems and methods

• US 7,554,096 B2
• Filed: 11/15/2006
• Issued: 06/30/2009
• Est. Priority Date: 10/16/2003
• Status: Active Grant

• Current Assignee: Alis Corp. (Carl-Zeiss-Stiftung)
• Original Assignee: Alis Corp. (Carl-Zeiss-Stiftung)
• Inventors: Notte, John A. IV, Hill, Raymond, Farkas, Louis S. III, Ward, Billy W., Percival, Randall G.
• Primary Examiner(s): Wells; Nikita
• Application Number:
  US11/599,879
• Publication Number:
  US 20070221843A1
• Time in Patent Office: 958 Days
• Field of Search: 250/423.F, 250/423.R, 250/426, 250/492.21, 250/492.2
• US Class Current: 250/423.00F
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: H01J 2237/0807 Gas field ion sources [GFIS]
• CPC Class Codes: H01J 2237/202 Movement
• CPC Class Codes: H01J 2237/20228 Mechanical X-Y scanning
• CPC Class Codes: H01J 2237/2566 ion
• CPC Class Codes: H01J 2237/2623 Field-emission microscopes
• CPC Class Codes: H01J 2237/2812 Emission microscopes
• CPC Class Codes: H01J 2237/30438 Registration
• CPC Class Codes: H01J 2237/3174 Etching microareas
• CPC Class Codes: H01J 2237/31755 using ion beams
• CPC Class Codes: H01J 37/08 Ion sources; Ion guns
• CPC Class Codes: H01J 37/20 Means for supporting or positioning the object or the material; Means for adjusting diaphragms or lenses associated with the support
• CPC Class Codes: H01J 37/252 Tubes for spot-analysing by electron or ion beams; Microanalysers
• CPC Class Codes: H01J 37/28 with scanning beams H01J37/268, H01J37/292, H01J37/2955 take precedence
• CPC Class Codes: H01J 37/3056 for microworking, e. g. etching of gratings or trimming of electrical components
• CPC Class Codes: H01J 37/3174 Particle-beam lithography, e.g. electron beam lithography

Abstract

Ion sources, systems and methods are disclosed.

Claims

1. A system, comprising:

a gas field ion source comprising an electrically conductive tip,

wherein the gas field ion source is capable of interacting with a gas to generate an ion beam for a time period of one week or more without removing the electrically conductive tip from the system.

2. The system of claim 1, wherein the time period is two weeks or more.

3. The system of claim 1, wherein the time period is one month or more.

4. The system of claim 1, wherein the time period is two months or more.

5. The system of claim 1, wherein, during the time period, a current of the ion beam at a surface of a sample varies by 10% or less per minute.

6. The system of claim 1, wherein, during the time period, a current of the ion beam at a surface of a sample varies by 5% or less per minute.

7. The system of claim 1, wherein, during the time period, a current of the ion beam at a surface of a sample varies by 1% or less per minute.

8. The system of claim 1, wherein the ion beam has a reduced etendue of 1×

10<sup>−

16</sup> cm²srV or less.

9. The system of claim 1, wherein the ion beam has an etendue of 5×

10<sup>−

21</sup> cm²sr or less.

10. The system of claim 1, wherein the ion beam has a reduced brightness at the surface of the sample of 5×

10⁸ A/m²srV or more.

11. The system of claim 1, wherein the ion beam has a brightness at the surface of the sample of 1×

10⁹ A/cm²sr or more.

12. The system of claim 1, wherein the ion beam has a spot size with a dimension of 10 nm or less at the surface of the sample.

13. The system of claim 1, wherein the ion beam has an ion beam current at the surface of the sample of one nA or less.

14. The system of claim 13, wherein the ion beam current at the surface of the sample is 0.1 fA or more.

15. The system of claim 1, wherein the ion beam has an energy spread at the surface of the sample of five eV or less.

16. The system of claim 1, further comprising the sample, wherein the surface of the sample is five cm or more from the electrically conductive tip.

17. The system of claim 1, wherein the system is a gas field ion microscope.

18. The system of claim 1, wherein the system is a helium ion microscope.

19. The system of claim 1, wherein the system is a scanning gas field ion microscope.

20. The system of claim 1, wherein the system is a scanning helium ion microscope.

21. The system of claim 1, further comprising ion optics configured so that at least some ions in the ion beam pass through the ion optics before reaching the sample.

22. The system of claim 21, wherein the ion optics comprise electrodes and an aperture, the aperture being configured to prevent some of the ions in the ion beam from reaching the surface of the sample.

23. The system of claim 1, further comprising a mechanism coupled to the gas field ion source so that the mechanism can translate the electrically conductive tip, tilt the electrically conductive tip or both.

24. The system of claim 1, wherein the electrically conductive tip comprises a material selected from the group consisting of tungsten, carbon, tantalum, iridium, rhenium, niobium, platinum and molybdenum.

25. The system of claim 1, wherein the electrically conductive tip is a W(111) tip.

26. The system of claim 25, wherein the W(111) tip has a terminal atomic shelf that is a trimer.

27. The system of claim 1, wherein the electrically conductive tip has a terminal atomic shelf comprising one or more atoms, and 70% or more of the ions in the ion beam that reach a surface of the sample are generated via an interaction of the gas with a single atom of the one or more atoms of the terminal atomic shelf.

28. The system of claim 1, further comprising a coolant source thermally coupled to the gas field ion source so that during operation of the gas field ion source the temperature of the gas field ion source is 5K or more.

29. The system of claim 1, further comprising a cryogenic refrigerator thermally coupled to the gas field ion source so that during operation of the gas field ion source the temperature of the gas field ion source is 5K or more.

30. The system of claim 1, wherein the ion beam has a convergence half angle of 5 mrad or less at the surface of the sample.

31. The system of claim 1, wherein the gas field ion source comprises an electrically conductive tip having a terminal shelf with 20 atoms or less.

32. A system, comprising:

a gas field ion source capable of interacting with a gas to generate an ion beam for a time period of one week or more with a total interruption time of 10 hours or less.

33. The system of claim 32, wherein the total interruption time is five hours or less.

34. The system of claim 32, wherein the total interruption time is two hours or less.

35. The system of claim 32, wherein the total interruption time is one hour or less.

36. The system of claim 32, wherein the time period is two weeks or more.

37. The system of claim 32, wherein the time period is one month or more.

38. The system of claim 32, wherein the time period is two months or more.

39. The system of claim 32, wherein, during the time period, a current of the ion beam at a surface of a sample varies by 10% or less per minute.

40. The system of claim 32, wherein, during the time period, a current of the ion beam at a surface of a sample varies by 5% or less per minute.

41. The system of claim 32, wherein, during the time period, a current of the ion beam at a surface of a sample varies by 1% or less per minute.

42. The system of claim 32, wherein the gas field ion source comprises an electrically conductive tip, and the electrically conductive tip is not removed from the system during the time period.

43. The system of claim 32, wherein the ion beam has a reduced etendue of 1×

10<sup>−

16</sup> cm²srV or less.

44. The system of claim 32, wherein the ion beam has an etendue of 5×

10<sup>−

21</sup> cm²sr or less.

45. The system of claim 32, wherein the ion beam has a reduced brightness at the surface of the sample of 5×

10⁸ A/m²srV or more.

46. The system of claim 32, wherein the ion beam has a brightness at the surface of the sample of 1×

10⁹ A/cm²sr or more.

47. The system of claim 32, wherein the ion beam has a spot size with a dimension of 10 nm or less at the surface of the sample.

48. The system of claim 32, wherein the ion beam has an ion beam current at the surface of the sample of one nA or less.

49. The system of claim 48, wherein the ion beam current at the surface of the sample is 0.1 fA or more.

50. The system of claim 32, wherein the ion beam has an energy spread at the surface of the sample of five eV or less.

51. The system of claim 32, further comprising the sample, wherein the gas field ion source comprises an electrically conductive tip, and the surface of the sample is five cm or more from the electrically conductive tip.

52. The system of claim 32, wherein the system is a gas field ion microscope.

53. The system of claim 32, wherein the system is a helium ion microscope.

54. The system of claim 32, wherein the system is a scanning gas field ion microscope.

55. The system of claim 32, wherein the system is a scanning helium ion microscope.

56. The system of claim 32, further comprising ion optics configured so that at least some ions in the ion beam pass through the ion optics before reaching the sample.

57. The system of claim 56, wherein the ion optics comprise electrodes and an aperture, the aperture being configured to prevent some of the ions in the ion beam from reaching the surface of the sample.

58. The system of claim 32, further comprising a mechanism, the gas field ion source including an electrically conductive tip, the mechanism being coupled to the gas field ion source so that the mechanism can translate the electrically conductive tip, tilt the electrically conductive tip or both.

59. The system of claim 32, wherein the gas field ion source includes an electrically conductive tip that comprises a material selected from the group consisting of tungsten, carbon, tantalum, iridium, rhenium, niobium, platinum and molybdenum.

60. The system of claim 32, wherein the gas field ion source comprises a W(111) tip.

61. The system of claim 60, wherein the W(111) tip has a terminal atomic shelf that is a trimer.

62. The system of claim 32, wherein the gas field ion source has a terminal atomic shelf comprising one or more atoms, and 70% or more of the ions in the ion beam that reach a surface of the sample are generated via an interaction between the gas and a single atom of the one or more atoms of the terminal atomic shelf.

63. The system of claim 32, further comprising a coolant source thermally coupled to the gas field ion source so that during operation of the gas field ion source the temperature of the gas field ion source is 5K or more.

64. The system of claim 32, further comprising a cryogenic refrigerator thermally coupled to the gas field ion source so that during operation of the gas field ion source the temperature of the gas field ion source is 5K or more.

65. The system of claim 32, wherein the ion beam has a convergence half angle of 5 mrad or less at the surface of the sample.

66. The system of claim 32, wherein the gas field ion source comprises an electrically conductive tip having a terminal shelf with 20 atoms or less.