Temperature-insensitive structure design of micromachined resonant accelerometers

Abstract

Micromachined resonant accelerometers (MRAs), especially those devices fabricated by silicon on glass technology, suffer from temperature drift error caused by inherent thermal stress. This paper proposes two structure designs to attenuate the effect of thermal stress. The first MRA structure is realized by optimizing the locations of the bonding anchors and utilizing a special-shaped substrate to isolate the thermal stress generated during the die attach process. The second structure is designed using an isolation frame fixed by a single anchor to replace all dispersed anchors associated with the suspension beams and micro-levers. Simulated and experimental results show that both of the MRA structures can effectively reduce the thermal stress effect. The experimental results on one MRA prototype indicate that the differential temperature sensitivity reduces down to 1.9 μg/°C and its 15-day bias stability reaches 1.4 μg.