Scanning-electrostatic-force microscopy: Self-consistent method for mesoscopic surface structures

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Abstract
Scanning-electrostatic-force microscopy (SEFM) provides an efficient way to collect information of surface structures. The electrostatic force between the charged tip and the polarized sample cannot be derived analytically for samples with complex profiles and arbitrary dielectric distributions. In this paper we calculate the electrostatic force in the framework of self-consistent integral equation formalism, incorporating the image method to treat the coupling of substrate and tip. The simulation results show that the electrostatic force depends strongly on the bias voltage of tip, tip-sample distance, and dielectricity of the sample and substrate. The scanned force image is in good relation to the topography of the sample. The apparent size of the sample is approximately linear to the probe-sample distance. The force signal of densely arranged cubic dielectric pads is simply the superposition of forces signals of each pad alone. The interference effect of the electric field is not remarkable in SEFM.