CMOS MEMS accelerometer for long-term in vivo real-time small animal biological monitoring

A CMOS MEMS accelerometer is proposed for long term in vivo real time "free" small animal activity monitoring. The activity information along with other vital physiological signals such as blood pressure, temperature, EKG, etc. are critical for advanced biological and genetic research. The prototype sensor is designed and fabricated in a commercial 1.5 mum CMOS process, exhibiting a nominal sensing capacitance value of 540 fF with a designed sensitivity of 15 f/Fg and self resonance of 3 kHz. The device occupies an area of approximately 800 mum times 700 mum and can be integrated with CMOS interface and signal processing electronics on a same chip, thus substantially reducing form factor, power dissipation, and packaging complexity of the final implantable microsystem