A micro resonant acceleration sensor comprising silicon support with temperature isolator and quartz doubled ended tuning fork

Abstract

We present a micro resonant acceleration sensor based on the frequency shift of quartz double ended tuning fork (DETF). The two stiff ends of DETF are mounted on proof mass and temperature isolator structure of silicon support, respectively. Electrodes are coated on the four surfaces of the resonant beam to excite anti-phase vibration model to balance inner stress and torque. Stress in DETF beam shifts when the proof mass is applied to acceleration, which changes resonance frequency of DETF. The temperature isolator structure is designed to reduce the impact of thermal stress due to the difference of thermal expansion coefficient between quartz and silicon. The silicon support and DETF are fabricated based on the bulk micromachining technology. Self-excited circuit is also designed to excite DETF. The proposed sensor is simply packaged for measurement. The sensor takes advantages of both quartz and silicon materials to achieve a micro resonant sensor with simple processing for digital acceleration measurements.