Surface Micromachined Accelerometer with Increased Working Capacitance and Force Feedback Operation

A surface micromachined accelerometer has been realized by using a 10μm thick polysilicon layer. The sensor is designed as a differential capacitor and works in a force feedback mode to improve the sensor performance The evaluation circuit is realized as a seperate chip. The measured closed loop sensitivity is 8m V/g, the bandwidth is about 10kHz. A resolution of 0.1g and a linearity error of less than 1% is achieved for an measurement range of +/- 100 g.