Sensitivity study of surface stress biosensors based on ultrathin Si membranes

A study on the design of membrane based bimorph structures that can be used for the development of surface stress biosensors is presented. At first, the finite element analysis of cantilever based biosensors is evaluated utilizing analytical equations and published experimental results. The model that is selected simulates successfully the cantilevers' behavior and can be further expanded to more complicated structures. Therefore, we study the sensitivity of the membrane based surface stress biosensors and the effect that their geometrical parameters have on the sensor performance. Although membranes are less sensitive than the cantilevers, they attain interest in biological sensing because they can be used with capacitive readout, and thus have the potential for miniaturized sensor arrays. Based on the simulation results, we reveal the structure characteristics that should be considered in the design of the biosensors in the case of flat Si membranes.