基于单一敏感质量的三轴电容加速度计的设计

Design of Tri-axis Capacitive MEMS Accelerometer Based on Single Mass

设计了一种单一敏感质量的三轴电容加速度计。该器件采用全差分电容的检测方法,满足了灵敏度的设计要求并解决了三轴的交叉耦合问题,其独特的单一敏感质量结构减小了器件的整体尺寸,降低了成本。器件由外延多晶硅工艺实现了18μm的厚度制作,降低了热机械噪声,增大了检测电容,提高了灵敏度、分辨率和可靠性。ANSYS仿真结果表明,器件在3个轴向的灵敏度一致性好,抗干扰,测试结果和理论分析相符。该加速度计结构工艺简单,在消费电子领域有较好的应用前景。

The design,manufacture and test of a tri-axis capacitive MEMS accelerometer based on the single mass are presented.This acceleration sensor takes advantage of single mass structure to reduce the MEMS dimensions and decrease the cost.To match the sensitivity design requirement,the differential capacitive detection is utilized,and the sensitivity coupling problem of three orthogonal axes is avoided.The mass and comb finger structure are based on the EPI-poly process to realize the 18μm thickness.The detection capacitance,sensitivity and reliability are improved,and the mechanical noise is decreased.The ANSYS simulation results show that the sensor is consistent in three axes with good anti jamming capability.The testing results agree with the simulation data.Thanks to the simple structure and process,the single-mass tri-axis capacitive accelerometer can be widely used in consumer electronics applications.