Flexural contact in MEMS stiction

Adhesive force between two solid surfaces can lead to stiction failure of the micro-electro-mechanical systems (MEMS) device. The competition between the adhesive force and the beam restoring force determines whether the stiction occurs or not. Previous models assume that the stuck beam deforms either as the arc-shape or the S-shape, which causes significant differences in the measurements of adhesion and disputations among researchers. The contact mechanics model presented in this paper shows that the assumptions of the arc-shape and S-shape on the beam deformation over-simplify the problem; both the arc-shaped deformation and S-shaped deformation significantly deviate from the real ones. The previous theories are shown to be incompatible with the recent experimental results. The model presented in this paper attempts to explain those new experimental results and resolve some disputations on the previous models. The instabilities of jump-in during loading process and jump-off during unloading process are also incorporated in this model.