SILICON BULK-MICROMACHINED INTERDIGITATED DIFFERENTIAL CAPACITIVE ACCELEROMETER

A kind of silicon bulk-micromachined interdigitated differential capacitive accelerometer structure is presented. The operation principle, optimization of the structure design and the fabrication sequence for this accelerometer are also discussed. On the basis of the discussion, a set of optimized structure design parameters is obtained. Compared with the surface micromachined capacitive accelerometer ADXL50, the differential capacitance of this accelerometer can be more than 20 times larger. At the same time, the parasitic capacitance between the device and the substrate can be also avoided with glass adopted as the substrate. Furthermore, there is barely any stress in this device for single crystalline silicon is used as the structure material. The requirements for signal detection circuit of this accelerometer are less demanding, so it is more convenient to fabricate.