Design and characterization of a CMOS compatible poly-SiGe lowg capacitive accelerometer

Abstract

This paper presents the design and characterization of a CMOS compatible low-g capacitive accelerometer, fabricated in a low thermal budget poly-SiGe MEMS technology. The out-of-plane single axial device features a large effective capacitive surface, low cross talk and a robust beam suspension. The structural layer thickness of the accelerometer is 4 μm. First, the accelerometer design is described, followed by an overview of the fabrication and characterization process. The released devices have been electro-statically analyzed, with an impedance analyzing system, in order to verify the DC responses of the devices to bias voltage sweeps. Then, the devices are encapsulated in a DIL (Dual-in Line) package for the vibration and angular characterizations. The dynamic responses of the poly-SiGe devices are compared to those of a piezoelectric reference accelerometer. The results demonstrate for the first time the achievability of fabricating large sensing area, low g accelerometers with the above-CMOS poly-SiGe technology.