Highly sensitive micromachined capacitive pressure sensor with reduced hysteresis and low parasitic capacitance

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    Abstract

    This paper describes the design and fabrication of a capacitive pressure sensor that has a large capacitance signal and a high sensitivity of 76 pF/bar in touch mode operation. Due to the large signal, problems with parasitic capacitances are avoided and hence it is possible to integrate the sensor with a discrete components electronics circuit for signal conditioning. Using an AC bridge electronics circuit a resolution of 8 mV/mbar is achieved. The large signal is obtained due to a novel membrane structure utilizing closely packed hexagonal elements. The sensor is fabricated in a process based on fusion bonding to create vacuum cavities. The exposed part of the sensor is perfectly flat such that it can be coated with corrosion resistant thin films. Hysteresis is an inherent problem in touch mode capacitive pressure sensors and a technique to significantly reduce it is presented.
    Original languageEnglish
    JournalSensors and Actuators A: Physical
    Volume154
    Issue number1
    Pages (from-to)35-41
    ISSN0924-4247
    DOIs
    Publication statusPublished - 2009

    Keywords

    • Fusion bonding
    • Hysteresis
    • Capacitive pressure sensor

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