Design and fabrication of a new miniaturized capacitive accelerometer

A novel mercury-based capacitive accelerometer has been designed and fabricated. The accelerometer features a highly symmetrical cubic structure and capacitive coupling of the high-frequency input voltage, which uses a mercury drop for spring material and flexible interconnection layer between the capacitor plates. The device is mounted on a standard IC package with dimensions of 5 mm × 5 mm × 5 mm. The structure, working principle, fabrication, and mathematical model of the accelerometer are presented. Since the accelerometer uses a mercury drop as its sensitive electrode instead of a solid, which is commonly used in traditional accelerometers, the conflict between the requirements of high shock and high sensitivity is solved. The measurement results show a sensitivity of 0.2 mV (m s−2)−1 with a corresponding resolution of 0.01 ms−2, off-axis sensitivity of <5% and good linearity in the output voltage for accelerations up to at least 10 m s−2.