High-Speed Force Curve Measurement based on Atomic Force Observer

Abstract

Atomic Force Microscope (AFM) is a scanning probe microscope with nanoscale resolution, and it is an indispensable device for nanotechnology. Since the AFM probe physically touches the sample surface, there are rising expectations for sample dynamics measurement. One common measurement mode is the force curve measurement. In the force curve measurement, the atomic force is detected by the spring constant of the cantilever. In high speed measurement, however, the cantilever oscillates at its resonance frequency and cannot detect the atomic force. This paper proposes novel methods to identify cantilever dynamics and to measure the force curve at high speed using atomic force observer (AFO). The effectiveness of the proposed measurement method is demonstrated by using simulations and experiments. Furthermore, the robustness of the AFO against modeling error and its convergence are discussed.