Cantilevers for a magnetically driven atomic force microscope

• US 5,866,805 A
• Filed: 09/12/1996
• Issued: 02/02/1999
• Est. Priority Date: 05/19/1994
• Status: Expired due to Term

• Current Assignee: Keysight Technologies, Inc.
• Original Assignee: Arizona Board of Regents (University of Arizona)
• Inventors: Jing, Tianwei, Lindsay, Stuart M., Han, Wenhai
• Primary Examiner(s): LARKIN, DANIEL SEAN
• Application Number:
  US08/710,191
• Time in Patent Office: 873 Days
• Field of Search: 73/105, 250/306, 250/307
• US Class Current: 73/105
• CPC Class Codes: B82Y 35/00 Methods or apparatus for measurement or analysis of nanostructures
• CPC Class Codes: G01Q 10/06 Circuits or algorithms therefor
• CPC Class Codes: G01Q 30/14 Liquid environment
• CPC Class Codes: G01Q 60/32 AC mode
• CPC Class Codes: G01Q 60/38 Probes, their manufacture, or their related instrumentation, e.g. holders
• CPC Class Codes: Y10S 977/849 with scanning probe
• CPC Class Codes: Y10S 977/86 Scanning probe structure
• CPC Class Codes: Y10S 977/865 Magnetic force probe
• CPC Class Codes: Y10S 977/871 with environmental regulation means
• CPC Class Codes: Y10S 977/872 Positioner
• CPC Class Codes: Y10S 977/873 Tip holder
• CPC Class Codes: Y10S 977/875 with tip detail

Abstract

A force sensing cantilever for use in a scanning probe microscope has both a top side and a bottom side. From the bottom side extends a probe tip. The bottom side is coated with a thin film of a first material and the top side is coated with a thin film of a second material. The first and second materials may be the same or they may be different. The materials and thicknesses of the respective films are selected so as to create opposing forces to counter the tendency of such cantilevers to bend when a thin film is applied to only one side thereof.

Claims

1. A force sensing cantilever for use in a scanning probe microscope, said cantilever comprising:

a cantilever structure having a top side and a bottom side, said bottom side including a probe tip disposed downwardly therefrom;

a film of a first material which is not magnetizable disposed over said bottom side and said probe tip; and

a film of a second material which is magnetizable disposed over said top side, and wherein said first material is different from said second material, said first and second materials and the thicknesses of the respective films being selected so as to counter the tendency of said cantilever structure to bend when a film is applied only to one side thereof.

2. A cantilever according to claim 1 in which said cantilever structure comprises silicon nitride.

3. A cantilever according to claim 1 wherein said second material comprises Nd/Fe/Bo.

4. A force sensing cantilever for use in a scanning probe microscope, said cantilever comprising:

a cantilever structure having a top side and a bottom side, said bottom side including a probe tip disposed downwardly therefrom;

a film of a first material comprising Cr which is not magnetizable disposed over said bottom side and said probe tip; and

a film of a second material which is magnetizable disposed over said top side, and wherein said first material is different from said second material.

5. A cantilever according to claim 4 wherein said second material comprises Nd/Fe/Bo.

6. A method of fabricating a force sensing cantilever for a scanning probe microscope comprising the steps of:

forming a cantilever structure having a top side, a bottom side, and a probe tip extending downwardly from said bottom side;

placing the cantilever in a sputter deposition chamber;

sputter depositing a first material which is not a magnetizable material onto the bottom side of the cantilever to form a film of said first material; and

sputter depositing a second material which is magnetizable onto the top side of the cantilever to form a film of said second material, said first and second materials and the thicknesses of the respective films being selected so as to counter the tendency of said cantilever structure to bend when a film is applied only to one side thereof.

7. A method according to claim 6 wherein said first material and said second material are different.

8. A method according to claim 7 further comprising the step of:

magnetizing the cantilever in a selected direction.

9. A method according to claim 6 further comprising the step of:

magnetizing the cantilever in a selected direction.

10. A method of fabricating a force sensing cantilever for a scanning probe microscope comprising the steps of:

forming a cantilever structure having a top side, a bottom side and a probe tip extending downwardly from said bottom side;

placing the cantilever in a sputter deposition chamber;

selecting a non-magnetic material and thin film thickness to counter the bending force that will be applied by a deposited film of a selected magnetic material;

sputter depositing said non-magnetic material onto the bottom side of the cantilever to said selected thickness; and

sputter depositing said selected magnetic material onto the top side of the cantilever.

11. A method according to claim 10 wherein said cantilever comprises silicon nitride.

12. A method according to claim 11 wherein said non-magnetic material comprises Cr.

13. A method according to claim 12 wherein said magnetic material comprises a rare-earth magnetic alloy.

14. A method according to claim 13 wherein said rare-earth magnetic alloy comprises Nd/Fe/Bo.

15. A method according to claim 13 wherein said magnetic material comprises an alloy selected from the group consisting of:

Nd/Fe/Bo, samarium cobalt, aluminum nickel cobalt, and combinations of the foregoing.

16. A force sensing cantilever for use in a scanning probe microscope, said cantilever comprising:

a cantilever structure with a spring constant of less than 1 N/m and having a top side and a bottom side, said bottom side including a probe tip disposed downwardly therefrom;

a film of a first material which is not magnetizable disposed over said bottom side and said probe tip; and

a film of a second material which is magnetizable disposed over said top side, and wherein said first material is different from said second material, said first and second materials and the thicknesses of the respective films being selected so as to counter the tendency of said cantilever structure to bend when a film is applied only to one side thereof.

17. A cantilever according to claim 16 in which said cantilever structure comprises silicon nitride.

18. A cantilever according to claim 16 wherein said second material comprises a rare earth magnetic material comprising alloys selected from the group consisting of:

Nd/Fe/Bo, samarium cobalt, aluminum nickel cobalt, and combinations of the foregoing.

19. A method of fabricating a force sensing cantilever for a scanning probe microscope comprising the steps of:

forming a cantilever structure having a spring constant of less than 1 N/m, a top side, a bottom side, and a probe tip extending downwardly from said bottom side;

placing the cantilever in a sputter deposition chamber;

sputter depositing a first material which is not magnetizable onto the bottom side of the cantilever to form a film of said first material; and

sputter depositing a second material which is magnetizable onto the top side of the cantilever to form a film of said second material, wherein said first and second materials are different and the thicknesses of the respective films are selected so as to counter the tendency of said cantilever structure to bend when a film is applied only to one side thereof.

20. A method according to claim 19 further comprising the step of:

magnetizing the cantilever in a selected direction.

21. A method of fabricating a force sensing cantilever for a scanning probe microscope comprising the steps of:

forming a cantilever structure having a spring constant of less than 1 N/m, a top side, a bottom side, and a probe tip extending downwardly from said bottom side;

placing the cantilever in a sputter deposition chamber;

selecting a non-magnetic material and thin film thickness to counter the bending force that will be applied by a deposited film of a selected magnetic material;

sputter depositing said non-magnetic material onto the bottom side of the cantilever to said selected thickness; and

sputter depositing said selected magnetic material onto the top side of the cantilever.

22. A method according to claim 21 wherein said cantilever comprises silicon nitride.

23. A method according to claim 22 wherein said non-magnetic material comprises Cr.

24. A method according to claim 23 wherein said magnetic material comprises a rare-earth magnetic alloy.

25. A method according to claim 24 wherein said rare-earth magnetic alloy comprises a material selected from the group consisting of:

Nd/Fe/Bo, samarium cobalt, aluminum nickel cobalt, and combinations of the foregoing.