Focusing lens for electron emitter with shield layer

• US 6,741,016 B2
• Filed: 06/14/2001
• Issued: 05/25/2004
• Est. Priority Date: 06/14/2001
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Benning, Paul J., Knight, William R, Regan, Michael J.
• Primary Examiner(s): Patel, Ashok
• Assistant Examiner(s): HODGES, MATTHEW P
• Application Number:
  US09/882,933
• Publication Number:
  US 20020193036A1
• Time in Patent Office: 1,076 Days
• Field of Search: 313/306, 313/307, 313/308, 313/309, 313/293, 313/300, 313/303
• US Class Current: 313/309
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G11B 9/10 using electron beam; Record carriers therefor G11B9/08 takes precedence see provisional also G11B11/03
• CPC Class Codes: G11B 9/14 using microscopic probe means , i.e. recording or reproducing by means directly associated with the tip of a microscopic electrical probe as used in Scanning Tunneling Microscopy [STM] or Atomic Force Microscopy [AFM] for inducing physical or electrical perturbations in a recording medium; Record carriers or media specially adapted for such transducing of information marking using electrical current B41M5/20; measuring roughness or irregularity of surfaces G01B7/34; details of scanning-probe microscopes G01Q
• CPC Class Codes: G11B 9/1418 Disposition or mounting of heads or record carriers G11B17/00 and G11B19/00 take precedence
• CPC Class Codes: G11C 11/23 using electrostatic storage on a common layer, e.g. Forrester-Haeff tubes or William tubesG11C11/22 takes precedence
• CPC Class Codes: H01J 3/022 with microengineered cathode, e.g. Spindt-type

Abstract

An electron lens is used for focusing electrons from a cathode to an anode. The lens includes a first conductive layer with a first opening at a first distance from the cathode. The first conductive layer is held at a first voltage. The lens also includes a second conductive layer with a second opening at a second distance from the first conductive layer and a third distance from the anode. The second conductive layer is held at a second voltage substantially equal to the voltage of the anode. The first and second openings are chosen based on the first voltage, the second voltage, the first distance, the second distance and the third distance. The opening focuses the electrons emitted from the cathode onto the anode to a spot size preferably less than 40 nanometers. The force created between the cathode and anode is minimized by the structure of the lens.

Claims

1. An electrostatic lens for focusing electrons from a cathode to an anode, comprising:

a first conductive layer having a first opening at a first distance from the cathode, the first conductive layer held at a first voltage; and

a second conductive layer having a second opening at a second distance from the first conductive layer and a third distance to the anode layer, the second conductive layer held at a second voltage substantially equal to a voltage of the anode;

wherein the first opening and the second opening are about the same diameter, the first voltage less than a voltage of the cathode that is less than the second voltage, the first distance is between one and one-half the sum of the second distance and the third distance to focus the electrons emitted from the cathode onto the anode to a spot size less than 40 nanometers.

2. The electron lens of claim 1 wherein the the second distance is the thickness of a dielectric layer disposed on the first conductive layer.

3. The electron lens of claim 1 wherein the third distance is equal to or less than about 2 micrometers.

4. The electron lens of claim 1 wherein the first and second openings have a diameter about 7.2 micrometers, and the first and second distances are about 5 micrometers.

5. The electron lens of claim 1 wherein the force created between the cathode and the anode is less than about 0.03 Newtons/cm².

6. The electron lens of claim 1 wherein the spot size is less than about 10 nanometers.

7. The electron lens of claim 1 wherein the sensitivity to lens and shield geometry due to fabrication process variations is minimized.

8. The electron lens of claim 1 wherein the difference between the first voltage and the second voltage is about 700 volts.

9. The electron lens of claim 1 wherein the first conductive layer and the second conductive layer are formed using semiconductor thin-film technology.

10. The electron lens of claim 1 wherein the cathode layer comprises at least one spindt-tip emitter.

11. The electron lens of claim 1 wherein the cathode comprises at least one flat emitter.

12. A focused electron emitter, comprising:

a emitter layer at a first potential;

a lens layer disposed over a first distance from the emitter layer having a first opening and second potential;

a dielectric layer disposed on the lens layer; and

a shield layer disposed over a second distance from the lens layer on the dielectric layer and having a second opening substantially the same diameter as the first opening and held at a third potential;

wherein a focused electron beam is formed on an anode held at the third potential at a third distance from the shield layer.

13. The focused electron emitter of claim 12 wherein the sum of the second distance and the third distance is between about one to about two times the first distance.

14. The focused electron emitter of claim 12 wherein the emitter layer comprises at least one spindt-tip.

15. The focused electron emitter of claim 12 wherein the emitter layer comprises at least one flat emitter.

16. The focused electron emitter of claim 12 wherein the first distance and the second distance are substantially equal.

17. The focused electron emitter of claim 12 wherein the first distance is about 5 micrometers.

18. The focused electron emitter of claim 12 wherein the diameter of the first opening is about 7.2 micrometers.

19. The focused electron emitter of claim 12 wherein the force created between the emitter layer and the anode layer is less than 0.03 Newtons/cm².

20. The focused electron emitter of claim 12 wherein the focused beam creates a focused spot size of less than 40 nanometers on the anode.

21. The focused electron emitter of claim 12 wherein the focused beam creates a focused spot size of less than 10 nanometers on the anode.

22. The focused electron emitter of claim 12 wherein the difference between the first potential and the second potential is greater than 500 volts.

23. The focused electron emitter of claim 12 wherein the third distance is equal to or less than about 2 micrometers.

24. A mass storage device comprising at least one focused electron emitter of claim 12.

25. An electronic device comprising at least one mass storage device of claim 24.

26. A display device comprising at least one focused electron emitter of claim 12.

27. An electronic device comprising at least one display device of claim 26.

28. A field emission device for creating a focused electron beam on an anode, comprising:

a cathode layer having at least one electron emitter;

a first dielectric layer disposed on the cathode layer;

a focusing lens including,

a lens layer disposed on the first dielectric layer;

a second dielectric layer disposed on the lens layer; and

a shield layer disposed on the second dielectric layer and interposed between the lens layer and the anode, the shield layer at about the same potential as the anode wherein the electrostatic attraction between the lens layer and the anode is reduced.

29. The field emission device of claim 28 wherein the sum of the distance between the lens layer and the shield layer and the distance between the shield layer and the anode is between about one to about two times the distance between the lens layer and the cathode layer.

30. The field emission device of claim 28 wherein the distance of the lens layer from the cathode layer and the distance of the shield layer from the lens layer are substantially equal.

31. The field emission device of claim 28 wherein distance of the lens layer from the cathode layer is about 5 micrometers.

32. The field emission device of claim 28 wherein lens layer and the shield layer include an opening for creating the focused electron beam, the openings having substantially the same diameter.

33. The field emission device of claim 32 wherein the diameter of the opening in the lens layer is about 7.2 micrometers.

34. The field emission device of claim 28 wherein the force created between the cathode layer and the anode is less than 0.03 Newtons/cm².

35. The field emission device of claim 28 wherein the focused electron beam creates a focused spot size of less than 40 nanometers on the anode.

36. The field emission device of claim 28 wherein the focused electron beam creates a focused spot size of less than 10 nanometers on the anode.

37. The field emission device of claim 28 wherein lens layer and the shield layer have a voltage potential difference greater than 500 volts.

38. The field emission device of claim 28 wherein the distance between the shield layer and the anode is equal to or less than about 2 micrometers.

39. A mass storage device comprising at least one field emission device of claim 28.

40. An electronic device comprising at least one mass storage device of claim 39.

41. A display device comprising at least one field emission device of claim 28.

42. An electronic device comprising at least one display device of claim 41.

43. A field emission device for creating a focused electron beam on an anode, comprising:

means for creating a source of electrons;

means for focusing the source of electrons on the anode;

a dielectric layer disposed on the means for focusing; and

means for shielding the means for focusing from the anode to reduce electrostatic attraction forces by having the means for shielding at about the same potential as the anode, said means for shielding disposed on the dielectric layer between the means for focusing and the anode.

44. The field emission device of claim 43 wherein the sum of the distance between the means for focusing and the means for shielding and the distance between the means for shielding and the anode is about one to about two times the distance between the means for focusing and the means for creating a source of electrons.

45. The field emission device of claim 43 wherein the distance between the means for creating and the means for focusing and the distance between the means for focusing and the means for shielding are substantially equal.

46. The field emission device of claim 43 wherein the distance between the means for creating and the means for focusing is about 5 micrometers.

47. The field emission device of claim 43 wherein the means for focusing and the means for shielding include a first opening and a second opening having substantially the same diameter.

48. The field emission device of claim 43 wherein the means for focusing includes an opening having a diameter of about 7.2 micrometers.

49. The field emission device of claim 43 wherein the force created between the means for shielding and the means for creating is less than 0.03 Newtons/cm².

50. The field emission device of claim 43 wherein the focused beam creates a focused spot size of less than 40 nanometers on the anode.

51. The field emission device of claim 43 wherein the focused beam creates a focused spot size of less than 10 nanometers on the anode.

52. The field emission device of claim 43 wherein the means for focusing has a first potential and the means for shielding has a second potential substantially equal to the potential of the anode, and wherein the difference between the first potential and the second potential is greater than 500 volts.

53. The field emission device of claim 43 wherein the distance between the means for shielding and the anode is equal to or less than about 2 micrometers.

54. A mass storage device comprising at least one field emission device of claim 43.

55. An electronic device comprising at least one mass storage device of claim 54.

56. A display device comprising at least one field emission device of claim 43.

57. An electronic device comprising at least one display device of claim 56.

58. A method of making an electron lens for an electron emitting cathode for focusing an electron beam on an anode, comprising the steps of:

creating a lens layer a first distance from the electron emitting cathode, the lens layer having a first opening substantially centered over the electron emitting cathode;

creating a dielectric layer on the lens layer; and

creating a shield layer a second distance from the lens layer disposed on the dielectric layer and a third distance from the anode, the shield layer having a second opening substantially aligned with the first opening, wherein the sum of the second distance and the third distance is between about one to about two times the first distance.

59. The method of claim 58 wherein the first distance is substantially equal to the second distance.

60. The method of claim 58 wherein the first distance is about 5 micrometers.

61. The method of claim 58 wherein the third distance is equal to or less than about 2 micrometers.

62. The method of claim 58 wherein the diameter of the first opening is about 7.2 micrometers.