The device model we have investigated and fabricated in this study is illustrated in Figure 1. Comb electrodes are formed at the tip of a cantilever structure with a spring constant kz that vibrates in the out-of-plane direction (z-direction). Because both the upper and lower movements of the movable comb electrode equally cause a decrease of the overlapping area between the comb electrodes, the capacitance should be represented by an even function of the displacement z. Therefore, in this work, we modeled the capacitance by a Gaussian function form as