A MEMS Micro-g Capacitive Accelerometer Based on Through-Silicon-Wafer-Etching Process

Abstract

This paper presents a micromachined micro-g capacitive accelerometer with a silicon-based spring-mass sensing element. The displacement changes of the proof mass are sensed by an area-variation-based capacitive displacement transducer that is formed by the matching electrodes on both the movable proof mass die and the glass cover plate through the flip-chip packaging. In order to implement a high-performance accelerometer, several technologies are applied: the through-silicon-wafer-etching process is used to increase the weight of proof mass for lower thermal noise, connection beams are used to reduce the cross-sensitivity, and the periodic array area-variation capacitive displacement transducer is applied to increase the displacement-to-capacitance gain. The accelerometer prototype is fabricated and characterized, demonstrating a scale factor of 510 mV/g, a noise floor of 2 µg/Hz1/2 at 100 Hz, and a bias instability of 4 µg at an averaging time of 1 s. Experimental results suggest that the proposed MEMS capacitive accelerometer is promising to be used for inertial navigation, structural health monitoring, and tilt measurement applications.

Design and Modification of a High-Resolution Optical Interferometer Accelerometer

“…A modal analysis is used to verify the dynamic capability of the accelerometer [ 28 ]. A modal analysis is mainly applied to determine the natural frequency and mode shape of the structure.…”

An Integrated Gold-Film Temperature Sensor for In Situ Temperature Measurement of a High-Precision MEMS Accelerometer

“…The proposed gold-film temperature sensor was integrated on a MEMS high-precision accelerometer for in situ temperature measurement of the acceleration sensing element, as shown in Figure 11 . The reported MEMS high-precision accelerometer [ 18 ] consists of a silicon-based spring-mass system fabricated by through-wafer etching process [ 19 ] and matching electrodes on both the mass surface and the upper glass layer for area-change capacitive displacement transduction. The gold-film temperature sensor was fabricated on the accelerometer frame simultaneously with the capacitive electrodes.…”

Highly Sensitive Signal Processing Devices for Capacitive Transducers of Micromechanical Accelerometers

“…In the voltage-based or charge-based SPD, these voltage fluctuations are significantly amplified by the high-gain amplifier. This requires an increase of the proof mass to minimize the noise-floor and expand the dynamic range R D [7,8,13]. In contrast to this, there is no amplifier in the open-loop frequency-based SPD ( Figure 2).…”

“…There are many kinds of transducers in present micromechanical accelerometers, such as capacitive, piezo-resistive, electromagnetic, optical, thermal convective, acoustic waves resonant, field emission, tunnel transducers and so on [6]. The micromechanical accelerometers with capacitive transducers are widely used due to relatively simple transducer structure, high-sensitivity, reliability, thermal stability, excellent linearity, resolution, bandwidth, good compatibility with integrated circuits technology, and consequently low cost [7][8][9][10][11][12][13][14].…”