Investigation of the influence of the geometric parameters of AFM cantilevers on the resonant frequency of their oscillations

Abstract

This paper presents the results of theoretical and experimental studies aimed at studying the influence of the basic geometric parameters of micromechanical cantilevers on the resonant frequency of their oscillations. The dependences of the oscillation frequency on the length of the cantilever beam, obtained based on mathematical modeling are theoretically investigated by the finite element method. In experimental studies that used AFM cantilever beams, the beams were shortened stepwise by the method of local ion beam etching by focused ion beam (FIB) Ga+. After each step, the change in the resonant frequency of oscillations was monitored. It was found that the application of the FIB method allows you to accurately change the geometric parameters of the probe beams, which, in turn, allows you to change the resonant frequency of cantilever oscillations with high accuracy. During the analysis of the obtained dependences of the resonant frequency of oscillations on the geometric parameters of the beams, it was found that a decrease in the length of the cantilever from 110 to 80 μm leads to an approximately twofold increase in the resonant frequency of oscillations of the cantilever from 320 to 620 kHz. The obtained graphs of the theoretical and experimental dependencies are compared, which showed a good correlation of the results.