A Reliable Liquid-Based Highly Sensitive Micro Thermoresistive Convective Accelerometer by Using $0.35 \mu \mathrm{M}$ CMOS MEMS Technology

In this paper, the Rayleigh-number ( Ra) based compact model was used to design and fabricate a reliable liquid-based micro thermosensitive convective accelerometer (MTCA) with dual-differential-detectors (DD) design using the 0.35μm CMOS MEMS technology with a two-order-of-magnitude increase in sensitivity (43.8mV/g, gain=1) compared with the-state-of-art MTCA. Aluminum with higher temperature coefficient of resistance (TCR, α = 3.3×10
^-3
/K) is adopted as the sensing material instead of polysilicon (0.9×10
^-3
/K). Besides, the DD design is implemented to double the output compared with the conventional single-differential-detector (SD) design. Furthermore, the Parylene-C is used for reliable conformal water-proof coating & ca 9-year-lifetime) for MTCA, resulting in excellent normalized sensitivity using alcohol ( 3,344 μV/g/mW) as the working fluid. Nonlinear MTCA responses using different working fluids are revealed both theoretically and experimentally, useful for design optimization of MTCA.