Triaxial Capacitive Accelerometer Based On The Monolithic Integration Of CMOS MEMS

IC technology and micro-machining technology prepared micro-machinedaccelerometer, with its small size, light weight, low power consumption, low cost,easy of integration, strong anti-overload and mass characteristics has become corecomponents of Micro Inertial Measurement Unit. Capacitive accelerometer due toits low-noise, high-precision, low-power consumption, has been one successfulapplication of micro-machined accelerometers. This paper focuses on the carMEMS sensors project design based on a monolithic CMOS MEMS technologyintegrated multi-layer metal structure three-axis capacitive accelerometer. Specificwork and results are as follows：(1)Comparative analysing the advantages, disadvantages and feasibility ofacceleration sensor of the different kinds of detection principle, choosing thecomb-shaped capacitor structure as the direction of the theme of the thesis；(2)For detection method of comb-type capacitor, designing simultaneouslydetect three axial acceleration of the overall sensor structure, the overall detectionstructure of the sensor comprises: detect the XY-axis mass,detect the Z-axismass,same layer set comb move comb uniform-comb structure XY-axis sensitiveunit, intertwined metal layer Z-axis sensitive unit,support XY-axis mass L-shapedelastic beam,support Z-axis mass elastic beam, anchor point；(3)Simulating and verifying sensor structure overall mechanical properties byusing finite element software, optimizing the sensor size according to the verifiedresults,and getting the horizontal direction and Z-axis mechanical sensitivity andresonance frequency of the sensor；(4)Designing one kind of double carrier low resistance preamplifier detectioncircuit, focusing on the determination of the parameters of the amplifier;；(5)Elaborating on the fabrication steps of preparating sensor by using theCMOS MEMS0.35um TSMC technology；...