164m Direct Force Balance Method for Afm Lateral Force Calibration

David B. Asay, Pennsylvania State University, 123 Fenske Lab, University Park, PA 16802 and Seong H. Kim, Department of Chemical Engineering, Pennsylvania State University, 123 Fenske Lab, University Park, PA 16802.

A new and simple calibration method for the atomic force microscope (AFM) is developed. Until now, calibration of the AFM for lateral force microscopy has been difficult and nontrivial. This non-scanning method is based on direct force balances on surfaces with known slopes. From the collection of force-distance measurements on surfaces with known slopes, the lateral calibration is determined. This method requires a substrate with known slopes, the z-motion of the piezo calibrated, and the normal spring constant known. This technique determines not only the lateral detector sensitivity (N/V) but also the detector off-set (V/m) and off-centering angle (á) for asymmetric cantilevertip geometries. Because it is non-scanning, the AFM cantilever can be calibrated without dulling the tip.