AVS 49th International Symposium
    Nanometer Structures Tuesday Sessions
       Session NS-TuP

Paper NS-TuP1
Calibration Methods for Displacement and Cantilever Stiffness in AFM

Tuesday, November 5, 2002, 5:30 pm, Room Exhibit Hall B2

Session: Nanometer Structures A
Presenter: N.A. Burnham, Worcester Polytechnic Institute
Authors: G.A. Matei, Worcester Polytechnic Institute
E.J. Thoreson, Worcester Polytechnic Institute
N.A. Burnham, Worcester Polytechnic Institute
X. Chen, University of Nottingham
C.H. Hodges, University of Leeds
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The laser beam in our AFM was placed half on and half off a cantilever that was hanging freely above a reflective surface. The resulting two beams interfered and the interference could be detected at the photodiode, yielding a simple and accurate means of calibrating the scanner displacement. This approach will be extended to the calibration of the amplitude of oscillating cantilevers. Also, we compared the experimentally determined values of stiffness for ten cantilever probes using four different methods@footnote 1@. For rectangular silicon cantilever beams of well-defined geometry, the approaches all yield values within seventeen percent of the manufacturer's nominal stiffness. One of the methods is new, based on the acquisition and analysis of thermal distribution functions of the oscillator's amplitude fluctuations. We evaluate this method in comparison to the three others and recommend it for its ease of use and broad applicability. @FootnoteText@ @footnote 1@ N.A. Burnham, X. Chen, C.S. Hodges, et al., submitted to Review of Scientific Instruments.