Eight Beam Clamped Piezoresistive Acceleration Sensor And Test Circuit

The micro accelerometer is now widely used in automotive electronics, military, aerospace, geological exploration, disaster prediction and so on as a new type of inertial device. The piezoresistive micro accelerator has the advantage fast frequency response, high sensitivity, high accuracy, easy miniaturization, and with strong ability to work normally in hazard radiation environment.In this thesis, we designed a 8-end fixed beam piezoresistive accelerometer. Because of its high resonance frequency, it has a very wide frequency response range. The device has the performance with a tiny cross-axis sensitivity by optimizing the combination of resistance. This article details are given as followingFirstly, we designed a model of sensor's sensitivity, natural frequency, cross-axis sensitivity. The same time, the theoretical calculations of sensitivity, natural frequency, cross-axis sensitivity of the theoretical calculations are verified with software SOLIDWORKS by using the finite element analysis simulation. And finally determine the optimized piezoresistive micro accelerometer size, the overall chip size is 3200μm×3200μm×900μm, the mass size is 1400μm×1400μm×420μm, beam size is 800μm×20μm×20μm.In this size, the sensor's sensitivity is 24.5μV/g, natural frequency is 2.4kHz.Secondly, the analysis of the KOH anisotropic etching and graphic design of compensation pattern and analysis of the silicon-glass bonding process theory with process parameters are included. And then, by using SILVACO software to determine the final resistivity and doping junction depth. Finally use a mature process to develop a Reliable process, making the device easy to fabricate, to ensure the device design is Rational.At last, we designed a circuit with the temperature compensation and adjustable output range block with Amplifiers.