An optimization technique for performance improvement of gap-changeable MEMS accelerometers

Zakriya Mohammed, Ghada Dushaq, Aveek Chatterjee, Mahmoud Rasras

Research output: Contribution to journalArticle

Abstract

This paper demonstrates the design and optimization of single- and dual-axis capacitive accelerometers. Detailed analysis together with fabrication and characterization results are reported. The designs utilize a simplified comb structure to detect capacitance change between rotor and stator fingers. By optimizing the gap spacing (finger gap and anti-finger gap), the devices are designed to yield high capacitance change as a function of the proof mass displacement. It was found that there is a critical anti-gap spacing for a selected finger gap at which the device sensitivity is the highest (ratio of 3.45: 1). Designs are first optimized using Finite Element Analysis (FEA) tools. Initial simulation results indicated a differential capacitive sensitivity of 80fF/g and 68fF/g for single- and dual -axis accelerometers, respectively. The capacitance-voltage (CV) measurements exhibited a parabolic behavior which is an important characteristic for these type of accelerometers. Furthermore, results show a rest capacitance of 16.42 pF and sensitivity of 35 fF/g for single-axis accelerometer. Overall, the devices have excellent sensitivity, high linearity, and low cross-axis sensitivity. The accelerometers are fabricated using GlobalFoundries’ Inertial Measurement Unit (IMU) platform and have a compact footprint of 1.8 mm × 1.8 mm.

Original languageEnglish (US)
Pages (from-to)203-216
Number of pages14
JournalMechatronics
Volume54
DOIs
StatePublished - Oct 2018

Keywords

  • Accelerometer
  • Anti-gap spacing
  • Capacitive sensitivity
  • Comb fingers
  • Finger gap spacing, Spring constant

ASJC Scopus subject areas

  • Mechanical Engineering
  • Computer Science Applications
  • Electrical and Electronic Engineering

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