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A microaccelerometer with highly reliable, wafer-level packaged MEMS sensing element and fully differential, continuous time, low noise, BiCMOS interface circuit is fabricated. The MEMS sensing element is fabricated on a (111)-oriented SOI wafer by using the SBM (Sacrificial/Bulk Micromachining) process. To protect the silicon structure of the sensing element and enhance the reliability, a wafer level hermetic packaging process is performed by using a silicon-glass anodic bonding process. The interface circuit is fabricated using 0.8 µm BiCMOS process. The capacitance change of the MEMS sensing element is amplified by the continuous-time, fully-differential transconductance input amplifier. A chopper-stabilization architecture is adopted to reduce low-frequency noise including 1/f noise. The fabricated microaccelerometer has the total noise equivalent acceleration of 0.89 µg/√Hz, the bias instability of 490 µg, the input range of ±10 g, and the output nonlinearity of ±0.5 %FSO.

A simulation model of vibratory capacitive microgyroscope and its driving loop is designed using SPICE. The vibratory microgyroscope is basically microelectromechanical system; therefore the simulation model should be expressed mechanical and electrical properties. To modelling the microgyroscope, the Analog Behavioral Model is used. In order to design a driving loop of vibratory microgyrosope, the the Barkhausen criteria is considered. The co-simulation of MEMS sensing element and its interface circuit is performed. The SPICE simulation model of the vibratory microgyrocope is designed, and the driving loop of the microgyroscope is simulated using the designed simulation model. The simulation results demonstrate the validity of the designed model and its interface circuit