Methods of imaging in probe microscopy

• US 7,441,447 B2
• Filed: 10/10/2006
• Issued: 10/28/2008
• Est. Priority Date: 10/07/2005
• Status: Expired due to Fees

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Degertekin, Fahrettin L., Balantekin, Mujdat, Onaran, Abidin G.
• Primary Examiner(s): CYGAN, MICHAEL T
• Application Number:
  US11/548,005
• Publication Number:
  US 20070295064A1
• Time in Patent Office: 749 Days
• Field of Search: 731/05, 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 20/04 Self-detecting probes, i.e. wherein the probe itself generates a signal representative of its position, e.g. piezoelectric gauge
• CPC Class Codes: G01Q 60/38 Probes, their manufacture, or their related instrumentation, e.g. holders
• CPC Class Codes: G01Q 70/02 Probe holders

Abstract

In accordance with an embodiment of the invention, there is a force sensor for a probe based instrument. The force sensor can comprise a detection surface and a flexible mechanical structure disposed a first distance above the detection surface so as to form a gap between the flexible mechanical structure and the detection surface, wherein the flexible mechanical structure is configured to deflect upon exposure to an external force, thereby changing the first distance.

Claims

1. A system for generating definable nano-scale properties of a sample, comprising:

an integrated force sensor positioned in proximity to and detecting said sample;

a first output signal corresponding to detected material properties of said sample;

a second output signal corresponding to detected surface properties of said sample;

a hardware component for receiving said force sensor output signals and selectively transmitting received signals; and

a software component for controlling operating parameters of said hardware component, receiving transmitted signals from said hardware component, determining material and surface properties of said sample according to received data, and outputting said determinations, wherein said integrated force sensor comprises;

a detection surface;

at least one reflective diffraction grating provided in connection with said detection surface;

a force sensor attached to said detection surface, said force sensor comprising;

a flexible mechanical structure disposed a first distance above the detection surface so as to form a gap between the flexible mechanical structure and the detection surface, wherein the flexible mechanical structure is configured to independently deflect upon exposure to an external force, thereby changing the first distance; and

a probe tip disposed on an outer surface of the flexible mechanical structure;

an actuator coupled to each of the diffraction grating and flexible mechanical structure and configured to electrostatically apply force to the flexible mechanical structure; and

a detector configured to measure deflection of said flexible mechanical structure.

2. The system according to claim 1, wherein said integrated force sensor is configured to oscillate said probe tip at its resonance frequency.

3. The system according to claim 1, wherein said integrated force sensor is configured to follow topography and oscillate said probe tip with a periodic signal at a frequency which is different from the resonance frequencies of the flexible mechanical structure.

4. The system according to claim 1, wherein the grating is configured to provide optical interferometric detection.

5. The system according to claim 1, wherein the material properties include adhesion, Van der Waals forces, electrostatic forces, elastic, and viscoelastic properties.

6. The system according to claim 1, wherein outputting said determinations is by a graphic display.

7. The system according to claim 1, wherein the output signal corresponding to surface properties is generated by an electrostatic actuation of said integrated force sensor.

8. The system according to claim 1, wherein the output signal corresponding to material properties is generated by diffraction based detection of said sample with said integrated force sensor.

9. The system according to claim 1, wherein the input signals are analog.

10. The system according to claim 1, wherein the input signals are digitized for transmission to a software component.

11. The system according to claim 1, wherein the hardware component extracts at least a peak repulsive force (PRF) and peak attractive force (PAF) from the input signal.

12. The system according to claim 1, wherein the hardware component further extracts data corresponding to tip-sample contact duration and slope of the force.

13. The system according to claim 1, wherein said hardware component includes programmable devices configured to collect material dependent parameters in any tip-sample contact mechanics model.

14. The system according to claim 13, wherein said tip-sample contact model is selected from the group comprising Hertzian, Derjaguin-Muller-Toporov, Burnham-Colton-Pollock, Johnson-Kendall-Roberts-Sperling, and Maugis mechanics.

15. The system according to claim 1, wherein said hardware component further outputs analog and digital signals to any of a controller and a force sensor.

16. The system according to claim 1, wherein said software component determines material properties of said sample with a tip-sample interaction model.

17. The system according to claim 16, wherein said software component further processes and generates an image representing input material properties.

18. The system according to claim 1, wherein the electrostatic actuator moves the force sensor to perform fast intermittent contact mode imaging.

19. The system according to claim 1, wherein said system obtains direct measurement of dynamic sensor-sample interactions and output a corresponding signal.

20. The system according to claim 1, includes a piezo scanner.

21. The system according to claim 1, wherein the output signals are tip displacement signals.

22. The system according to claim 1, wherein one or more diffraction orders can be detected.

23. The system according to claim 1, wherein the definable properties include qualitative and quantitative sample properties.

24. The system according to claim 1, wherein the sample includes surface properties and material properties.

25. The system according to claim 24, wherein the surface properties include surface topography.

26. The system according to claim 1, wherein the properties include mechanical, physical, chemical, biological, electrical, and magnetic properties by type, position, and amount.

27. The system according to claim 1, wherein the tip is positioned substantially normal to a sample surface.

28. A method of determining nano-scale properties of a sample, comprising:

positioning an integrated force sensor in proximity to said sample;

detecting said sample with at least said integrated force sensor;

selectively outputting at least one signal corresponding to detected material properties of said sample and corresponding to detected surface properties of said sample;

providing a hardware component for receiving said force sensor output signals and selectively transmitting received signals; and

providing a software component for controlling operating parameters of said hardware component, receiving transmitted signals from said hardware component, determining material and surface properties of said sample according to received data, and outputting said determinations, wherein said integrated force sensor comprises;

a detection surface;

at least one reflective diffraction grating provided in connection with said detection surface;

a force sensor attached to said detection surface, said force sensor comprising;

a flexible mechanical structure disposed a first distance above the detection surface so as to form a gap between the flexible mechanical structure and the detection surface, wherein the flexible mechanical structure is configured to independently deflect upon exposure to an external force, thereby changing the first distance; and

a probe tip disposed on an outer surface of the flexible mechanical structure;

an actuator coupled to each of the diffraction grating and flexible mechanical structure and configured to electrostatically apply force to the flexible mechanical structure; and

a detector configured to measure deflection of said flexible mechanical structure.

29. The method according to claim 28, wherein said integrated force sensor is configured to oscillate said probe tip at its resonance frequency.

30. The method according to claim 28, wherein said integrated force sensor is configured to follow topography and oscillate said probe tip with a periodic signal at a frequency which is different from the resonance frequencies of the flexible mechanical structure.

31. The method according to claim 28, wherein the grating is configured to provide optical interferometric detection.

32. The method according to claim 28, wherein the material properties include adhesion, Van der Waals forces, electrostatic forces, elastic, and viscoelastic properties.

33. The method according to claim 28, wherein the output signal corresponding to surface properties is generated by an electrostatic actuation of said integrated force sensor.

34. The method according to claim 28, wherein the output signal corresponding to material properties is generated by diffraction based detection of said sample with said integrated force sensor.

35. The method according to claim 28, further comprising digitizing the input signals for transmission to the software component.

36. The method according to claim 28, further comprising extracting, by the hardware component, at least a peak repulsive force (PRF) and peak attractive force (PAF) from the input signal.

37. The method according to claim 36, further comprising extracting, by the hardware component, data corresponding to tip-sample contact duration and slope of the force.

38. The method according to claim 28, wherein said hardware component includes programmable devices configured to collect material dependent parameters in any tip-sample contact mechanics model.

39. The method according to claim 38, wherein said tip-sample contact model is selected from the group comprising Hertzian, Derjaguin-Muller-Toporov, Burnham-Colton-Pollock, Johnson-Kendall-Roberts-Sperling, and Maugis mechanics.

40. The method according to claim 28, wherein said hardware component further outputs analog and digital signals to any of a controller and a force sensor.

41. The method according to claim 28, wherein said software component determines material properties of said sample with a tip-sample interaction model.

42. The method according to claim 28, wherein said software component further processes and generates an image representing input material properties.

43. The method according to claim 28, further comprising obtaining direct measurement of dynamic sensor-sample interactions and outputting a corresponding signal.

44. The method according to claim 28, wherein the output signals are tip displacement signals.

45. The method according to claim 28, wherein one or more diffraction orders can be detected.

46. The method according to claim 28, wherein the sample properties include qualitative and quantitative sample properties.

47. The method according to claim 28, wherein the sample properties include mechanical, physical, chemical, biological, electrical, and magnetic properties by type, position, and amount.

48. The method according to claim 28, wherein the tip is positioned substantially normal to a sample surface.