Study of the flexural sensitivity and resonant frequency of an inclined AFM cantilever with sidewall probe

Abstract

The resonant frequency and sensitivity of an atomic force microscope (AFM) cantilever with assembled cantilever probe (ACP) have been analyzed and a closed-form expression for the sensitivity of vibration modes has been obtained. The proposed ACP comprises an inclined cantilever and extension, and a tip located at the free end of the extension, which makes the AFM capable of topography at sidewalls of microstructures. Because the extension is not exactly located at one end of the cantilever, the cantilever is modeled as two beams. In this study, the effects of the interaction stiffness and damping, and also some geometrical parameters of the cantilever on the resonant frequencies and sensitivities are investigated. Afterwards, the influence of the interaction stiffness and damping, and the geometrical parameters such as the angles of the cantilever and extension, the connection position of the extension and the ratio of the extension length to the cantilever length on the sensitivity and resonant frequency are investigated. The results show that the greatest flexural modal sensitivity occurs at a small contact stiffness of the system, when the connection position and damping are also small. The results also indicate that at low values of contact stiffness, an increase in the cantilever slope or a decrease in the angle between the cantilever and extension can rise the resonant frequency while reduces the sensitivity.