Development and Characterization of a CMOS-MEMS Accelerometer With Differential LC-Tank Oscillators

Author

Yi Chiu ; Hao-Chiao Hong ; Po-Chih Wu

Author_Institution

Dept. of Electr. & Comput. Eng., Nat. Chiao Tung Univ., Hsinchu, Taiwan

Volume

22

Issue

6

fYear

2013

fDate

Dec. 2013

Firstpage

1285

Lastpage

1295

Abstract

This paper presents a CMOS-MEMS accelerometer based on differential LC-tank oscillators. Two LC-tank oscillators composed of differential MEMS capacitors and suspended inductors were designed and fabricated by standard TSMC 0.18 μm CMOS processes and post-CMOS dry etching. The outputs of the differential oscillators are mixed and the output frequency of the mixer is proportional to the capacitance change caused by the external acceleration. The device has been characterized and has a mechanical resonance frequency of 7 kHz, absolute sensitivity of 3.62 MHz/g, relative sensitivity of 1.9×10^-3 Δf/f₀/g, in-axis nonlinearity of 1.2%FS, bias stability of 2.1 mg, and average noise floor of 0.205-0.219 mg/√Hz in the frequency range of 15-250 Hz.

Keywords

CMOS integrated circuits; LC circuits; accelerometers; capacitors; etching; inductors; microfabrication; microsensors; oscillators; CMOS-MEMS accelerometer; TSMC CMOS processes; average noise floor; bias stability; capacitance change; differential LC-tank oscillators; differential MEMS capacitors; external acceleration; frequency 15 Hz to 250 Hz; frequency 7 kHz; in-axis nonlinearity; mechanical resonance frequency; mixer; post-CMOS dry etching; sensitivity; size 0.18 mum; suspended inductors; Accelerometers; Capacitors; Micromechanical devices; Oscillators; Resonant frequency; Sensitivity; Sensors; Accelerometer; Allan´s deviation; CMOS MEMS; LC tank oscillator; differential capacitor; frequency output;

fLanguage

English

Journal_Title

Microelectromechanical Systems, Journal of

Publisher

ieee

ISSN

1057-7157

Type

jour

DOI

10.1109/JMEMS.2013.2282419

Filename

6631467