Method and device of using a scanning probe microscope

Patent metadata

Field	Value
Publication number	US-11112426-B2
Application number	US-201615573137-A
Country	US
Kind code	B2
Filing date	May 11, 2016
Priority date	May 11, 2015
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

A scanning probe microscope for high-speed imaging and/or nanomechanical mapping including a scanning probe comprising a cantilever with a tip at the distal end, and means for modulating a tip-sample distance separating the tip from an intended sample to be viewed with the microscope, the means for modulating being adapted to provide a direct cantilever actuation.

First claim

The invention claimed is:

1. A method for characterising a surface of a sample using atomic force microscopy with a cantilever acting as both actuator and sensor, the method comprising the steps of:
generating an oscillating motion between a tip of the cantilever of the atomic force microscope and the surface of the sample by deforming at least a part of the cantilever to bring the tip of the cantilever in contact with the surface of the sample for a tip-sample interaction;
recording a deflection of the cantilever resulting from the tip-sample interaction as a first signal;
extracting the tip-sample interaction as a second signal from the first signal by removing a background signal;
determining a peak force from the extracted second signal;
comparing the peak force to a predetermined setpoint force to determine an error signal;
generating a control signal from the error signal; and
actuating a z-actuator using the control signal to maintain the peak force at the predetermined setpoint force,
wherein the cantilever includes an actuation coating and a detection coating, each of the coatings made of a different material, and each of the coatings is arranged at a different location on the cantilever.

2. The method of claim 1 , wherein the background signal includes a signal of the deflection resulting from the tip-sample interaction caused by the cantilever deformation to generate tip-sample distance modulation.

3. The method of claim 1 , wherein the step of recording the cantilever signal includes a step of reading a light beam.

4. The method of claim 3 , wherein the step of generating the oscillating motion caused by the deformation of at least a part of the cantilever uses a photothermal device as a modulation, and both a device generating the light beam and the photothermal device include a single laser.

5. The method of claim 1 , wherein the step of generating the oscillating motion caused by the deformation of at least a part of the cantilever is performed by a modulation device configured to provide a deformation of an entirety of the cantilever.

6. The method of claim 1 , wherein the step of generating the oscillating motion caused by the deformation of at least a part of the cantilever is performed by a modulation device configured to provide a partial deformation of the cantilever.

7. The method of claim 1 , wherein the step of generating the oscillating motion caused by the deformation of at least a part of the cantilever is configured to achieve a predefined motion.

8. The method of claim 7 , wherein the predefined motion compensates for the background signal.

9. The method of claim 1 , further comprising the step of:
thermally bending the cantilever to provide a feedback motion.

10. The method of claim 9 , wherein the step of thermally bending is configured to enable the feedback motion using a combination of a piezo scanner and the bending of the cantilever.

11. An atomic force microscope configured to perform the method of claim 1 .

12. The method of claim 1 , wherein the detection coating is arranged at a free end of the cantilever, and the actuation coating is arranged at a base of the cantilever.

13. The method of claim 1 , wherein the detection coating is arranged to cover an entire side of the cantilever.

14. The method of claim 1 , wherein the step of recording is performed by strain sensing of the cantilever, and the detection coating includes a piezoresistive, electrothermal, or piezoelectric device.

Assignees

• Ecole Polytechnique Fed Lausanne Epfl

Inventors

• Fantner Georg Ernest
• Adams Jonathan David
• Nievergelt Adrian Pascal

Classifications

• G01Q10/045 Primary

  Self-actuating probes, i.e. wherein the actuating means for driving are part of the probe itself, e.g. piezoelectric means on a cantilever probe · CPC title

• G01Q10/065

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

• G01Q60/32

  AC mode · CPC title

• G01Q20/02 Primary

  by optical means · CPC title