Electrothermally Tunable Accelerometer with Small Tuning Voltage and Very Large Sensitivity Tuning Range

This paper reports an electrothermally tunable accelerometer with very large tuning range. The device was fabricated in a SOI substrate. The proof mass in the proposed accelerometer was excited by electrostatic force at a carrier frequency. The applied vibration modulated the oscillating amplitude of the proof mass which was detected by piezoresistive signals. Differential bias voltages ±V
B
were applied to the sensing piezoresistors and, at the same time, heated the resonant beam for electrothermal tuning. With an applied bias/tuning voltage in the range of ±1.3 V to ±1.6 V, the measured sensitivity was tuned from 4.0 nV/g to 24.6 nV/g, corresponding to a tunability of 1000 %/V.