The SOI Micro-Accelerometer Fabricated by Sacrificial Process

Abstract

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.