The monolithic integrated technology of MEMS was discussed. First discussed the advantages and difficulties faced by the MEMS monolithic integration technology. Second the features and the process of the mainstream MEMS monolithic integration technology was introduced. And finally put forward a SOI MEMS monolithic integration technology, the technology with no high-temperature process, Post-CMOS integrated solution, compatible with the CMOS process. This technology can achieve high aspect ratio, high-performance micro-inertial devices..

This paper presents an experimental technique which illustrates to the student an application of Newton's law, the use of an accelerometer, and numerical double integration of the acceleration to obtain displacement. The simple impact experiment consists of a falling rigid projectile striking a sample. Data analysis utilizes Newton's law and double integration of the accelerometer output to obtain the dynamic load-deflection curve for the sample. An oscilloscope, digital data transfer to a PC, and manipulation of the data using spreadsheet software are incorporated in the experiment.

This paper presents the fabricationof SOI micro-accelerometer by using the sacrificial process. The structure ofthe SOI micro-accelerometer is designed and analyzed by the finite element modeling.As for the fabrication issue, the problem of electrode metal layer to standagainst HF etching is first studied. Second, to prevent the over-etching of theBOX layer during structure releasing process, the etching rate of the BOX layeris carefully investigated and an optimal etching duration is obtained. Third,the adhesion phenomenon between comb fingers during releasing process isstudied and optimized finger geometry is proposed to solve such problem.Devices based on the sacrificial process is carried out successfully, themeasurement results show that the sensitivity of the accelerometer is about 35mV/g, with a maximal measurement error of 12mg, and a maximal nonlinear error of0.41% within 50g.

In order to develop the SOI micro-accelerometer front release process, this paper discusses in details the key technologies of the process. There are three problems need to be resolved: the corrosion of the electrode, the corrosion rate of the buried silicon dioxide layer as well as the anti-adhesion of the micro-structure. The corrosion characteristic of the electrode is studied, and a metal electrode of high ability of anti-HF acid corrosion is designed, after release of the micro-structure, the electrode does not fall off. The corrosion property of the buried silicon dioxide is studied, and the corrosion rate is exactly known for 2um and 5um thick buried silicon dioxide layer. Based on this, the buried silicon dioxide layer etching time can be controlled, preventing over-etching of the oxide layer. The adhesion of comb fingers and the mass with the substrate is settled at last. By electron microscopy tests, found that the process can get a good micro-structure surface, with smaller footing effects. By test, the sensitivity of the accelerometer is about 144.5mv/g.