The calibration of atomic force microscopes is essential for accurate and meaningful measurements. It is especially important when attempting to compare results from different instruments and different techniques. The above diagram shows a map of some AFM applications along with the calibrations that are necessary for each application. Some of the calibration methods of interest are dimensional, spring constant, lateral force, and tip-shape calibration. Dimensional calibration is important for virtually all AFM applications - the x, y, and z piezoelectric scanners should be in calibration and regularly checked - and the dimensional team at NPL provides traceable calibrating gratings for scanning probe microscopes. The calibration of tip-shape is also important for surface measurements and many quantification issues in scanning probe microscopy demand an accurate measure of the tip shape at its extremity. At NPL we are developing methods and materials to determine the AFM tip shape. Spring constant calibration is used to calibrate the AFM deflection force from nanometres into Newtons and is extremely important for quantitative nano-force experiments. In the Surface & Nanoanalysis Group we are also reviewing and developing methods to calibrate the lateral force spring constant of an AFM cantilever.

Selected Publications

[1] Improved methods and uncertainty analysis in the calibration of the spring constant of an atomic force microscope cantilever using static experimental methods, C A Clifford, M P Seah, Meas. Sci. Technol. 20 (2010) 125501.

[2] Simplified drift characterization in scanning probe microscopes using a simple two-point method, C A Clifford and M P Seah, Meas. Sci. Technol. 20 095103 (2009).

[3] The determination of atomic force microscope cantilever spring constants via dimensional methods for nanomechanical analysis, C A Clifford and M P Seah, Nanotechnology, 16, 1666-1680 (2005).

If you want advice and help in calibrating AFMs, or require PDF copies of the publications, please contact us below.

Contact: Charles Clifford