Study And Design Of Capacitive Acceleration Micro-sensor Based On MEMS Technology

Information collecting(sensing), transmission(communication) and processing (cal- culating) consist of the three greatest foundation of modern information technology. With the rapid development of integrated circuit and MEMS technology, The research and application of the micro-Si sensor are greatly accelerated. At present, the micro-Si sensor is presenting the trend of commercialization and industrialization in every field. It has many advantages in bulk integration, cost, power consumption, reliability etc. As one of the important branch of sensors, acceleration sensors are paid more and more attention and be widely used in the field of navigation and aerospace, industry auto- mation , car airbag control and so on.In the dissertation, series types of micro-Si acceleration sensors were compared and the differential capacitive one was chosen to be studied. After its principle and fabrication process related were expounded, a symmetric"four cantilever beams-mass"structure was proposed, which is characterized by better linearity and sensitivity compa- red with the traditional deformable-membrane sensor.After the mechanics model of the differential capacitive acceleration sensor was made, finite element method was used to simulate its behavior, both static and dynamic. After the simulation, the distributed stress was lay out to validate the structure's ability of surviving under different loading. The results of the relation curves describe the relationships of the dimensions vs maximum displacement of the mass, the dimensions vs resonant frequency and the forced vibration responding of the mass's harmonic curve were also given. All these analysis are helpful to design such acceleration sensors. Finally, based on the MEMS technology presented, the structural dimension, fabricating process and layout designing were given.