Drift-insensitive distributed calibration of probe microscope scanner: Approach description
Channel: Rostislav Lapshin
Date: 2015-12-30

Elsevier's Audio Slides
http://audioslides.elsevier.com//ViewerSmall.aspx?source=1&doi=10.1016/j.apsusc.2015.10.108

A short introduction to the research article: R. V. Lapshin, Drift-insensitive distributed calibration of probe microscope scanner in nanometer range: Approach description, Applied Surface Science, vol. 359, pp. 629-636, 2015 (DOI: 10.1016/j.apsusc.2015.10.108). The article is available for free at the following link: http://www.niifp.ru/staff/lapshin/en/index.htm#approach2015


Slide 1. Title

Dear Colleagues!
My name is Rostislav Lapshin, I am a research scientist from the Institute of Physical Problems, Zelenograd, Moscow, Russian Federation.
I am going to briefly report about a new method, which is presented in my recent paper “Drift-insensitive distributed calibration of probe microscope scanner in nanometer range: Approach description” published in Applied Surface Science journal, in October 2015.


Slide 2. Main concept

The method of distributed calibration of a probe microscope scanner consists in a search for a net of local calibration coefficients in the process of automatic measurement of a standard surface, whereby each point of the movement space of the scanner can be defined by a unique set of scale factors


Slide 3. Applied methods

To eliminate the negative influence of noise, thermal drift and creep upon the distributed calibration results, the following methods were used:
1. Feature-oriented scanning.
2. Feature-oriented positioning.
3. Counter-scanned images.


Slide 4. Partitioning the scanner movement space with a net

At the beginning of the distributed calibration, the scanning space is partitioned with a square cell net where the nodes correspond to the absolute integer coordinates x, y, z of the scanner. During the calibration, three local calibration coefficients corresponding to axes X, Y, Z of the scanner are determined in the neighborhood of each net node.


Slide 5. Simplified flowchart of the distributed calibration

The procedure of distributed calibration is a sequence of three basic measurement operations: probe attachment (position 2), aperture scanning (position 3), and skipping (position 4), which are carried out in each net node of the scanner’s movement space.


Slide 6. Local calibration structure ABC of a standard surface

The attachment of the microscope probe to a surface feature allows capturing the feature located near the current net node and holding it within the “field of view” of the instrument. Scanning a small neighborhood called an aperture around the captured feature followed by recognition of topography in the obtained scan enables detecting the local calibration structure. Local calibration structure usually consists of three features A, B and C such that the distances between them are a priori known precisely. Atoms and/or interstices of the crystal lattice are used as features. To get the sought-for local calibration coefficients, the distances between the features A and B, A and C should be measured. Drift-insensitive measurement of these distances is carried out within the skipping operation.


Slide 7. Application fields

The developed calibration approach can be used in the following fields:
1. Accurate calibration of a probe microscope scanner in nanometer and subnanometer ranges.
2. Automatic characterization of lattice crystal parameters and surface defects.
3. Analysis and certification of SPM operation: measurements of thermal drifts, creeps, nonlinearities, nonorthogonalities, and spurious couplings.


Slide 8. Conclusions

1. A method of automatic distributed calibration has been suggested that allows excluding errors caused by static nonlinearities, nonorthogonalities and spurious couplings of a probe microscope piezoscanner.
2. The calibration database obtained during calibration is insensitive to microscope head thermal drift and piezoscanner creep because of the application of the feature-oriented scanning methodology.
3. The lattice constant of a crystal has been used as a nature length standard of nanometer range.

Finishing, I wish you all good luck in your research!