On detection and estimation in atomic force microscopy at different scan speeds*

A typical user of an atomic force microscope (AFM) judges the quality of information in the scan of a sample by the images generated from either the height signal (in contact mode) or the height, amplitude, and phase signals (in intermittent contact mode). As the speed of the tip across the sample is increased, these signals become corrupted by the dynamics in the actuators and other elements in the system. The amplitude and phase signals are derived from the motion of the cantilever during the scan and there have been alternative schemes proposed, such as transient mode AFM, that derive several other signals from the cantilever motion. In this work we study the utility of the height, amplitude, and other derived signals at different tip speeds for both imaging and for detection. The results are demonstrated through experiments using a grating sample scanned on an Agilent 5500 AFM.