A complementary metal oxide semiconductor (CMOS) compatible capacitive silicon accelerometer with polysilicon rib-style flexures

A silicon-based capacitive accelerometer with bulk silicon proof mass, poly silicon rib-style flexures, and detection circuits is fabricated and tested . A complementary metal oxide semiconductor (CMOS) compatible doping and an nealing process for 2-mu m-thick polysilicon used as a rib-style flexural b eam is developed to optimize the trade-off between the mechanical propertie s and electrical requirements. According to the anisotropic etch simulation and experimental results, we designed a convex corner compensation pattern and fabricated the proof mass. The open-loop gain of the fabricated switch ed capacitor integrator (SCI) is more than four thousands, and the common m ode range is from 0.8 V to 4.5 V. The fabricated accelerometer has sensitiv ity of 300 mV/g and capacitance change is 0.36 pF/g.