3D modeling of electrostatic interaction between atomic force microscopy probe and dielectric surface: Impact of tip shape and cantilever contribution

Techniques derived from the near-field microscopies and particularly the Atomic Force Microscopy (AFM) are presented as alternative techniques for space charge measurement compared to classical techniques due to their high sensitivity to the electrostatic force and an improved spatial resolution (few nanometers). One of the AFM derivative methods, which allow obtaining information on the charge state of the dielectric materials, is based on the measurement of Force Distance Curves (FDC) obtained by cycling approach and retraction of the AFM probe to the dielectric surface. In this paper, three-Dimensional (3D) simulation results for the electrostatic force between an AFM tip and the surface of a dielectric are presented for different AFM tip geometries. The first aim is to analyse the effect of tip shape on electrostatic contribution to force-distance curves. The second step consists in extracting cantilever contribution to electrostatic force. Finally, a model merging cantilever and tip shape contributions is developed. Simulation results are shown and compared with experimental data in order to validate our approach.