Modeling of touch mode capacitive sensors and diaphragms

The understanding of deflection, stress and strain of thin diaphragms with clamped edges under various loads including when the diaphragm touches the substrate is of great importance for designing and fabricating sensors and actuators. This article reports the finite element analysis (FEA) of these diaphragms for computer-aided design of touch mode capacitive pressure sensors. The advantages of the touch mode operation are good linearity in touched range, mechanically robust and large overload protection. These simulation results predict the change of the performance when the device parameters are varied and can be served as a design tool to arrive at a set of desired performance. The results also are useful for designing actuators with diaphragms.