Multi-Function Microelectromechanical Systems Implementation with an ASIC Compatible CMOS 0.18 mu m Process

Chih-Hsuan Lin*, Chao-Hung Song, Kuei-Ann Wen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

A multi-function microelectromechanical system (MEMS) with a three-axis magnetometer (MAG) and three-axis accelerometer (ACC) function was implemented with an application-specific integrated circuit (ASIC)-compatible complementary metal-oxide-semiconductor (CMOS) 0.18 mu m process. The readout circuit used the nested chopper, correlated double-sampling (CDS), noise reduction method; the frequency division multiplexing method; the time-division multiplexing method; and the calibration method. Sensing was performed by exciting the MEMS three-axis magnetometer at X/Y/Z axes mechanical resonant frequencies of 3.77/7.05/7.47 kHz, respectively. A modest die-level vacuum packaging resulted in in-plane and out-of-plane mechanical quality factors of 471-500 and 971-1000, respectively. The sensitivities of both the three-axis magnetometer with 2 mA driving current and the three-axis accelerometer were 7.1-10.7 uV/uT and 58.37-88.87 uV/ug. The resolutions of both the three-axis magnetometer with 2 mA driving current and three-axis accelerometer resolution were 44.06-87.46 nT/root Hz and 5.043-7.5 ng/root Hz. The resolution was limited by circuit noise equivalent acceleration (CNEM) and Brownian noise equivalent magnetic field (BNEM).

Original languageEnglish
Article number314
Number of pages22
JournalMicromachines
Volume12
Issue number3
DOIs
StatePublished - Mar 2021

Keywords

  • microelectromechanical systems
  • three-axis magnetometer
  • three-axis accelerometer

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