Atomic Force Microscopy Designs

Abstract

The design of an AFM has to enable two different tasks: First it has to allow for a xyz-motion during scanning (fine motion, or scan motion), for the acquisition of the surface topography. As the range of the piezo actuators performing this motion is limited to usually ${<}100\,\mathrm {\upmu m}$, the second task of an AFM design is to bring the cantilever tip and the sample initially so close together, that their distance is within the range of the z-fine motion. This task is called the coarse approach. Both of these tasks have to be satisfied while simultaneously maintaining a stiff mechanical structure with high resonance frequencies allowing for good vibration isolation and small (thermal) drift of the tip relative to the sample. In this chapter we discuss several types of coarse positioners as well as scanners for the fine motion and introduce the principles of some particular AFM designs.