Design, modeling and analysis of highly reliable capacitive microaccelerometer based on circular stepped-plate and small-area touch mode

A novel capacitive microaccelerometer is designed which can operate reliably under high load. The movable structure of the microaccelerometer is a stepped circular plate which is fully compliant. Touch mode is introduced into the microaccelerometer, and small-area touch mode as a novel touch mode for MEMS is developed without the use of dielectric layer. A switch electrode is located on the substrate to prevent the short circuit of variable capacitor’s electrodes. Accurate, time saving and memory space saving models are developed with a new numerical method and validated with finite element method and boundary element method. Electrostatic force is taken into account, so the touch analysis includes an electromechanical coupling analysis. Internal mechanical force such as thermal stress and residual stress which will induce abnormal operation also is taken into account. The novel microaccelerometer’s performance is analyzed, verifying the device’s reliability, verifying the developed models’ availability for performance analysis over full measurement range.