Feature-oriented scanning

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Feature-oriented scanning (FOS)[1][2][3][4] is a method of precision measurement of surface topography with a scanning probe microscope in which surface features (objects) are used as reference points for microscope probe attachment. With FOS method, by passing from one surface feature to another located nearby, the relative distance between the features and the feature neighborhood topographies are measured. This approach allows to scan an intended area of a surface by parts and then reconstruct the whole image from the obtained fragments. Beside the mentioned, it is acceptable to use another name for the method – object-oriented scanning (OOS).

Any topography element that looks like a hill or a pit in wide sense may be taken as a surface feature. Examples of surface features (objects) are: atoms, interstices, molecules, grains, nanoparticles, clusters, crystallites, quantum dots, nanoislets, pillars, pores, short nanowires, short nanorods, short nanotubes, viruses, bacteria, organelles, cells, etc.

Image of carbon film surface obtained by FOS method (AFM, tapping mode). Carbon clusters (hills) and intercluster spaces (pits) are used as surface features.

FOS is designed for high-precision measurement of surface topography (see Fig.) as well as other surface properties and characteristics. Moreover, in comparison with the conventional scanning, FOS allows obtaining a higher spatial resolution. Thanks to a number of techniques embedded in FOS, the distortions caused by thermal drifts and creeps are practically eliminated.

FOS has the following fields of application: surface metrology, precise probe positioning, automatic surface characterization, automatic surface modification/stimulation, automatic manipulation of nanoobjects, nanotechnological processes of "bottom-up" assembly, coordinated control of analytical and technological probes in multiprobe instruments, control of atomic/molecular assemblers, control of probe nanolithographs, etc.

Feature-oriented positioning

Feature-oriented positioning (FOP)[1][2] is a method of precise movement of the scanning microscope probe across the surface under investigation that is a simplified variant of the feature-oriented scanning (FOS). With FOP, no topographical image of a surface is acquired. Instead, a probe movement over surface features is only carried out from the start surface point A (neighborhood of the start feature) to the destination point B (neighborhood of the destination feature) along some route that goes through intermediate features of the surface. The method may also be referred to by another name — object-oriented positioning (OOP).

To be distinguished are a "blind" FOP when the coordinates of features used for probe movement are unknown in advance and FOP by existing feature "map" when the relative coordinates of all features are known, for example, when they were obtained during preliminary FOS. Probe movement by a navigation structure is a combination of the above by-point methods.

The FOP method may be used in bottom-up nanofabrication to implement high-precision movement of the nanolithograph/nanoassembler probe along the substrate surface. Moreover, after having traversed some route once, FOP may then be exactly repeated the required number of times. After movement to the specified position, an influence on the surface or manipulation of a surface object (nanoparticle, molecule, atom) is performed. All the operations are carried out in automatic mode. With multiprobe instruments, the FOP approach enables the application of any number of specialized technological and/or analytical probes successively to a surface feature/object or to a specified point in the feature/object neighborhood. That opens up the prospect of building a complex nanofabrication consisting of a large number of technological, measuring, and checking operations.

See also

References

  1. ↑ 1.0 1.1 R. V. Lapshin (2004). "Feature-oriented scanning methodology for probe microscopy and nanotechnology" (PDF). Nanotechnology (UK: IOP) 15 (9): 1135–1151. Bibcode:2004Nanot..15.1135L. doi:10.1088/0957-4484/15/9/006. ISSN 0957-4484.  (Russian translation is available).
  2. ↑ 2.0 2.1 R. V. Lapshin (2007). "Automatic drift elimination in probe microscope images based on techniques of counter-scanning and topography feature recognition" (PDF). Measurement Science and Technology (UK: IOP) 18 (3): 907–927. Bibcode:2007MeScT..18..907L. doi:10.1088/0957-0233/18/3/046. ISSN 0957-0233.  (Russian translation is available).
  3. ↑ R. V. Lapshin (2011). "Feature-oriented scanning probe microscopy" (PDF). In H. S. Nalwa. Encyclopedia of Nanoscience and Nanotechnology 14. USA: American Scientific Publishers. pp. 105–115. ISBN 1-58883-163-9. 
  4. ↑ R. V. Lapshin (2009). "Availability of feature-oriented scanning probe microscopy for remote-controlled measurements on board a space laboratory or planet exploration rover" (PDF). Astrobiology (USA: Mary Ann Liebert) 9 (5): 437–442. Bibcode:2009AsBio...9..437L. doi:10.1089/ast.2007.0173. ISSN 1531-1074. PMID 19566423. 

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