Development of a 3-DOF silicon piezoresistive micro accelerometer

This paper presents the design, fabrication and calibration results of a three degrees of freedom (3-DOF) micro accelerometer utilizing piezoresistive effect in Si. The sensor can detect three components of linear acceleration simultaneously. The sensing structure is a picture-frame type, i.e. the four sensing beams are surrounding the seismic mass. Therefore, the proposed sensor is smaller than the cross-beam type accelerometer having the same sensitivity. Frequency performance and noise problems are analyzed. The accelerometer has been fabricated by MEMS (micro electromechanical systems) technology, and packaged to a ceramic case. Preliminary calibration results show linear output voltage and small cross-sensitivity.