Prototype cantilevers for quantitative lateral force microscopy
Mark Reitsma, Richard S. Gates, Lawrence H. Friedman, Robert F. Cook
Prototype cantilevers that enable quantitative micro- to nano-scale surface force measurements using contact-mode atomic force microscopy (AFM) are presented. The Hammerhead cantilevers allow precise optical lever system calibrations for cantilever flexure and torsion, thus enabling quantitative friction measurements by lateral force microscopy at ultra-small scalescritically, the calibration can be performed in situ with force measurements, greatly increasing force measurement precision and accuracy. A methodology is presented for precise AFM instrument calibration and demonstrated to yield sub-percent relative uncertainties for optical-lever torque sensitivity on two different instruments. Finite element analysis of the loaded cantilevers, to assess the accuracy of the calibration methodology, indicates measurement errors of a few percent at most. The cantilevers are compatible with commercial AFM instrumentation and can be used for other AFM techniques such as contact imaging and dynamic mode measurements.