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

Kang Rao; Xiaoli Wei; Shaolin Zhang; Mengqi Zhang; Chenyuan Hu; Huafeng Liu; Liang-Cheng Tu

doi:10.3390/mi10060380

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

Micromachines (Basel). 2019 Jun 7;10(6):380. doi: 10.3390/mi10060380.

Authors

Kang Rao¹, Xiaoli Wei², Shaolin Zhang³, Mengqi Zhang⁴, Chenyuan Hu⁵, Huafeng Liu⁶, Liang-Cheng Tu^{7

8}

Affiliations

¹ MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physic, Huazhong University of Science and Technology, Wuhan 430074, China. raokang@hust.edu.cn.
² MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physic, Huazhong University of Science and Technology, Wuhan 430074, China. weixiaoli@hust.edu.cn.
³ MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physic, Huazhong University of Science and Technology, Wuhan 430074, China. zhangshaolin@hust.edu.cn.
⁴ MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physic, Huazhong University of Science and Technology, Wuhan 430074, China. zhangmengqi@hust.edu.cn.
⁵ MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physic, Huazhong University of Science and Technology, Wuhan 430074, China. chenyuanhu@hust.edu.cn.
⁶ MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physic, Huazhong University of Science and Technology, Wuhan 430074, China. huafengliu@hust.edu.cn.
⁷ MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physic, Huazhong University of Science and Technology, Wuhan 430074, China. tlc@hust.edu.cn.
⁸ Institute of Geophysics and PGMF, Huazhong University of Science and Technology, Wuhan 430074, China. tlc@hust.edu.cn.

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/Hz^1/2 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.

Keywords: MEMS; accelerometer; capacitance displacement transducer; micro-g; microfabrication; through-silicon-wafer-etching.

Abstract

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