Surface stress-induced deflection of a microcantilever with various widths and overall microcantilever sensitivity enhancement via geometry modification

The issues of surface stress-induced deflection of a microcantilever with various widths and overall microcantilever sensitivity enhancement of microcantilever-based biosensors are investigated in this paper. A remarkably precise and simple analytical formula for calculating surface stress-induced deflection of a microcantilever with various widths is deduced. Particularly, the effect of surface stress on the location of the microcantilever's neutral axis is considered. This explicit analytical formula is validated by the finite element method simulation. An analytical equation for computing the fundamental resonant frequency of a microcantilever with various widths is also derived. This paper explores the deflections and resonant frequencies of the microcantilevers having basic and modified shapes. It is found that minimizing the effective mass near the microcantilever's free end and the clamping width at the fixed end significantly enhances the overall microcantilever sensitivity. A novel microcantilever, which is expected to have much more excellent performance and overall sensitivity than the simple rectangular-shaped microcantilever, is proposed as sensor element in biological detection.