Atomic force microscopy controller and method

Patent metadata

Field	Value
Publication number	US-9229027-B2
Application number	US-201114001588-A
Country	US
Kind code	B2
Filing date	Feb 25, 2011
Priority date	Feb 25, 2011
Publication date	Jan 5, 2016
Grant date	Jan 5, 2016

Abstract

A method for determining a loop response for an apparatus for an atomic force microscope is disclosed. The method comprises: determining a loop response for an on-surface movement of a cantilever over a frequency range; determining a loop response for an off-surface movement of the cantilever over the frequency range; and adjusting an output of the controller at a frequency based on the loop response for the off-surface movement. An atomic force microscopy system is disclosed.

First claim

The invention claimed is:

1. A method for determining a loop response for an apparatus for an atomic force microscope, the method comprising:
determining a loop response for an on-surface movement of a cantilever over a frequency range;
determining a loop response for an off-surface movement of the cantilever over the frequency range; and
adjusting an output of the controller at a frequency based on the loop response for the off-surface movement.

2. A method as claimed in claim 1 , wherein the determining the loop response for off-surface movement of the cantilever comprises determining a resonance condition for the cantilever.

3. A method as claimed in claim 2 , further comprising, after the determining the resonance condition, reducing a gain of the controller at a frequency of the resonance condition.

4. A method as claimed in claim 2 , wherein the determining the loop response for the off-surface movement of the cantilever comprises providing a notch filter having a center frequency at the resonance condition.

5. A method as claimed in claim 2 , further comprising, after the adjusting, determining a second resonance condition for the cantilever.

6. A method as claimed in claim 5 , further comprising, after determining the second resonance condition, providing a second notch filter having a center frequency at the second resonance condition.

7. A computer readable medium having a computer readable program code embodied therein, the computer readable program code adapted to be executed by a computer to implement a method for determining a loop response for an apparatus for an atomic force microscope, the method comprising:
determining a loop response for an on-surface movement of a cantilever over a frequency range;
determining a loop response for an off-surface movement of the cantilever over the frequency range; and
adjusting an output of the controller at a frequency based on the loop response for the off-surface movement.

8. A computer readable medium as claimed in claim 7 , wherein the determining the loop response for off-surface movement of the cantilever comprises determining a resonance condition for the cantilever.

9. A computer readable medium as claimed in claim 8 , wherein the method further comprises, after the determining the resonance condition, reducing a gain of the controller at a frequency of the resonance condition.

10. A computer readable medium as claimed in claim 8 , wherein the determining the loop response for the off-surface movement of the cantilever comprises providing a notch filter having a center frequency at the resonance condition.

11. A computer readable medium as claimed in claim 8 , further comprising, after the adjusting, determining a second resonance condition for the cantilever.

12. A computer readable medium as claimed in claim 11 , further comprising, after determining the second resonance condition, providing a second notch filter at the resonance condition.

13. An atomic force microscopy (AFM) system, comprising:
a cantilever;
a probe tip connected at a first end of the cantilever;
an actuator connected to a second end of the cantilever; and
a controller configured to: determine a loop response for an on-surface movement of a cantilever over a frequency range; determine a loop response for an off-surface movement of the cantilever over the frequency range; and adjust an output of the controller at a frequency based on the loop response for the off-surface movement.

14. An AFM system as claimed in claim 13 , wherein the actuator is a piezoelectric actuator.

15. An AFM system as claimed in claim 13 wherein the controller determines a resonance condition for the cantilever.

16. An AFM system claimed in claim 15 , wherein the resonance condition is an off-surface resonance condition.

17. An AFM as claimed in claim 16 , wherein the controller comprises a notch filter at the off-surface resonance condition.

18. An AFM system as claimed in claim 15 , wherein the gain is less than zero at the off-surface resonance condition.

Assignees

• Moon Christopher Ryan
• Keysight Technologies Inc

Inventors

• Moon Christopher Ryan

Classifications

• G01Q60/24 Primary

  AFM [Atomic Force Microscopy] or apparatus therefor, e.g. AFM probes · CPC title

• G01Q10/065 Primary

  Feedback mechanisms, i.e. wherein the signal for driving the probe is modified by a signal coming from the probe itself · CPC title

• G01Q60/363

  Contact-mode AFM · CPC title

• B82Y35/00

  Methods or apparatus for measurement or analysis of nanostructures · CPC title

• G01Q10/00

  Scanning or positioning arrangements, i.e. arrangements for actively controlling the movement or position of the probe · CPC title