Limitations on accurate shape determination using amplitude modulation atomic force microscopy

B J Eves; R G Green

doi:10.1016/j.ultramic.2012.01.016

Limitations on accurate shape determination using amplitude modulation atomic force microscopy

Ultramicroscopy. 2012 Apr:115:14-20. doi: 10.1016/j.ultramic.2012.01.016. Epub 2012 Feb 7.

Authors

B J Eves¹, R G Green

Affiliation

¹ Institute for National Measurement Standards, National Research Council Canada, 1200 Montreal Road, Ottawa, Canada K1A 0R6. brian.eves@nrc-cnrc.gc.ca

PMID: 22459113
DOI: 10.1016/j.ultramic.2012.01.016

Abstract

The limitations of amplitude modulation atomic force microscopy to accurately measure the shape or form of features are investigated. The control feedback loop and the dynamics of the cantilever limit the response time of the atomic force microscope. Simply subtracting appropriately scaled amplitude (error) signal from the topography data significantly improves the accuracy of the data and can correct for the slow response time of the feedback loop. Two mechanisms were found to induce topographic errors independent of scan speed. The first is the change in tip/surface interaction at a step edge observed by comparison with results from a 'virtual' sample. The second is due to friction between the probe and sample but only for a specifically oriented step edge determined by the direction of oscillation of the cantilever.