Design, modelling and characterization of comb drive MEMS gap-changeable differential capacitive accelerometer

Ru Li, Zakriya Mohammed, Mahmoud Rasras, Ibrahim (Abe) M. Elfadel, Daniel Choi

Research output: Contribution to journalArticlepeer-review

Abstract

This paper presents design optimization, numerical modelling, fabrication and characterization of a single-axis comb drive MEMS gap-changeable differential capacitive accelerometer with a compact footprint of 2 mm × 2 mm. High sensitivity is achieved by optimizing the ratio of the anti-finger gap to finger gap spacing. It is found that a gap ratio of 3.44 leads to a displacement sensitivity of 0.0139 µm/g and a capacitive sensitivity of 80 fF/g. Finite element analysis is used to find the mode shape and frequency. Scanning electron microscope and capacitance-voltage measurements are employed to confirm the devices work. An enlarged static capacitance of 14.46 ± 0.42 pF is measured due to the enlarged stator anchor width. Electrical sensitivity of 35.93 mV/g is obtained by using the capacitance readout circuit at the system level, and the electrical sensitivity is practically constant over the frequency range of 100–200 Hz.

Original languageEnglish (US)
Article number108377
JournalMeasurement: Journal of the International Measurement Confederation
Volume169
DOIs
StatePublished - Feb 2021

Keywords

  • Accelerometer
  • Anti-gap spacing
  • Capacitive sensitivity
  • Comb fingers
  • MEMS

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering

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