The SOI micro-accelerometer fabricated by sacrificial process

摘要

This paper presents the fabrication of SOI micro-accelerometer by using the sacrificial process. The structure of the SOI micro-accelerometer is designed and analyzed by the finite element modeling. As for the fabrication issue, the problem of electrode metal layer to stand against HF etching is first studied. Second, to prevent the over-etching of the BOX layer during structure releasing process, the etching rate of the BOX layer is carefully investigated and an optimal etching duration is obtained. Third, the adhesion phenomenon between comb fingers during releasing process is studied and optimized finger geometry is proposed to solve such problem. Devices based on the sacrificial process is carried out successfully, the measurement results show that the sensitivity of the accelerometer is about 35 mV/g, with a maximal measurement error of 12mg, and a maximal nonlinear error of 0.41% within 50g.