Effects of gold patterning on the bending profile and frequency response of a microcantilever

We have systematically investigated the effect of various gold patterns on the bending profile and frequency response of a microcantilever. The gold patterns were deposited on the cantilever arrays using four types of shadow mask. The local bending profile, slope, and curvature varied depending on the area and position of the gold pattern. Also, the variations in the first three modes of the flexural resonance frequencies of the gold patterned cantilevers were measured to understand the opposing effects of mass loading and flexural rigidity; both of these parameters are dependent on the position and area of the gold pattern. The experimental results validated the theoretical one-dimensional model introduced by Tamayo [Appl. Phys. Lett. 89, 224104 (2006)] and our calculations using the finite element method. The gold patterns giving the maximum response of the mass loading and flexural rigidity change were determined by examining how the relative resonance frequency shifts as a function of the distance of the gold coating from the free end or clamping region. The results of this study can potentially be applied in the design of a microcantilever sensor in which pattern analysis is utilized to determine the presence of adsorbed biological and chemical molecules.