"Investigation of an Atomic Force Microscope (AFM) probe under electros" by Liton Ghosh

Date of Award

2008

Publication Type

Master Thesis

Degree Name

M.A.Sc.

Department

Electrical and Computer Engineering

Keywords

Applied sciences

Supervisor

Sazzadur Chowdhury

Rights

info:eu-repo/semantics/openAccess

Abstract

This thesis develops a readily computable closed-form analytical model to determine the pull-in voltage of an Atomic Force Microscope (AFM) probe under electrostatic actuation. The analytical model has been derived based on the Euler-Bernoulli beam theory, Taylor series expansion of the electrostatic energy stored in the AFM probe, and deflection function of the first natural mode of a cantilever beam. The model takes account of the electrostatic energy associated with the fringing field capacitances between the AFM probe cantilever and the substrate to develop a more accurate model of the stored electrostatic energy after the system is biased with a DC voltage. The developed energy model is then used to develop a highly accurate closed-form model for the pull-in voltage of the AFM probe. The developed closed-form model has been verified by comparing the model predicted values with published experimental results with a maximum deviation of 3.36%. The model has also been compared with a published curve model and 3-D electromechanical finite element analysis (FEA) results. The results are found to be in excellent agreement.

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