Stress-sensitive differential amplifiers using piezoresistive effects of MOSFETs and their application to three-axial accelerometers

Hidekuni Takao, Yoshinori Matsumoto, Makoto Ishida

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

A novel detection transducer, which can be applied to silicon integrated accelerometers and various mechanical sensors, is proposed. Mechanical quantities such as acceleration and pressure, etc., are translated to voltage signals with a 'stress-sensitive differential amplifier' (SSDA) using the piezoresistive effects of p-MOSFETs. Signal amplification and adjustment of the sensitivity are realized with the SSDA, and removal of cross-axis errors is also performed for accelerometers. The operation of the SSDA is analysed theoretically, and its application to an integrated three-axial accelerometer is presented as an effective example. The characteristics of SSDAs have been evaluated with the fabricated three-axial accelerometers. A Z-axis sensitivity of 11 mV g-1 is obtained even at a very small bias current (0.5 μA). By changing the operating point of the SSDA, the sensitivity at a sufficient bias current (above 10 μA) is adjustable from 25 to 55 mV g-1 in the Z-axis, and from 3.0 to 6.5 mV g-1 in the X- and Y-axes, respectively. Observed temperature drift of the sensitivity at a rate of -2000 ppm °C-1 can be compensated by the adjustability of the sensitivity. The SSDA is considered to be of possible use in an elemental detection circuit for many types of integrated mechanical sensors due to its many advantages.

Original languageEnglish
Pages (from-to)61-68
Number of pages8
JournalSensors and Actuators, A: Physical
Volume65
Issue number1
DOIs
Publication statusPublished - 1998 Feb 15
Externally publishedYes

Keywords

  • CMOS differential amplifiers
  • Inversion layer of MOSFET
  • Low power consumption
  • Mechanical sensors
  • Piezoresistive effect
  • Three-axial accelerometers

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering

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