# US 11,112,426 B2 · Method and device of using a scanning probe microscope

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- Number: US 11,112,426 B2
- Document ID: US11112426B2
- Status: Granted
- Kind: B2
- Application number: 15/573,137
- Filed: 2016-05-11
- Published: 2018-04-19
- Granted: 2021-09-07
- Earliest claimed: 2015-05-11
- Assignees: Ecole Polytechnique Federale De Lausanne (Epfl)
- Applicants: Ecole Polytechnique Federale De Lausanne (Epfl)
- Inventors: Georg Ernest Fantner; Jonathan David Adams; Adrian Pascal Nievergelt
- Web page: https://patentgrep.com/patent/US11112426B2

## CPC

- G01Q 20/02: by optical means
- G01Q 10/045: {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}
- G01Q 10/065: {Feedback mechanisms, i.e. wherein the signal for driving the probe is modified by a signal coming from the probe itself}
- G01Q 60/32: AC mode
- G01Q: SCANNING-PROBE TECHNIQUES OR APPARATUS; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBE MICROSCOPY [SPM]

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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

### Claim 4 (depends on 3)

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.

### Claim 5 (depends on 1)

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.

### Claim 6 (depends on 1)

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.

### Claim 7 (depends on 1)

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.

### Claim 8 (depends on 7)

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

### Claim 9 (depends on 1)

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

### Claim 10 (depends on 9)

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.

### Claim 11 (depends on 1)

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

### Claim 12 (depends on 1)

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.

### Claim 13 (depends on 1)

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

### Claim 14 (depends on 1)

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.