Simulation and characterization of a CMOS-MEMS gyroscope with parasitic-insensitive sensing

This paper reports the design and simulation results of the symmetrical and decoupled CMOS-MEMS gyroscope that utilizes the vertical capacitance change between the proof mass and sensing electrode. In order to reduce the lateral curling, a special beam with inversed-tapered cross-section has been designed. The gyroscope is fabricated through a standard 0.35 mum 2P4M CMOS-MEMS process. The dynamical response of the gyroscope is simulated using the MATLAB analytical simulator with a thermal noise of 0.0112 */s/Hz^1/2 and mechanical sensitivity of 0.4021 nm/deg/s at 50Hz bandwidth. In modal analysis, the modal frequency results using CoventorWare FEM simulator have 3% error compared to the formula calculation results. The on-chip parasitic-insensitive switched-capacitor sensing circuit is designed with a simulated sensitivity of 25.8938 V/pF. The sensitivity of the gyroscope is 9.16 mV/deg/s while the nonlinearity is 0.8937% at V_Driving=10V.