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Abstract

A microelectromechanical system (MEMS) accelerometer having separate sense and force-feedback electrodes is disclosed. The use of separate electrodes may in some embodiments increase the dynamic range of such devices. Other possible advantages include, for example, better sensitivity, better noise suppression, and better signal-to-noise ratio. In one embodiment, the accelerometer includes three silicon wafers, fabricated with sensing electrodes forming capacitors in a fully differential capacitive architecture, and with separate force feedback electrodes forming capacitors for force feedback. These electrodes may be isolated on a layer of silicon dioxide. In some embodiments, the accelerometer also includes silicon dioxide layers, piezoelectric structures, getter layers, bonding pads, bonding spacers, and force feedback electrodes, which may apply a restoring force to the proof mass region. MEMS accelerometers with force-feedback electrodes may be used in geophysical surveys, e.g., for seismic sensing or acoustic positioning.

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First Claim