压阻式高g值加速度传感器温度补偿设计

Temperature compensation design of piezoresistive high-g acceleration sensor

该文针对压阻式传感器在环境温度变化时会引起灵敏度非线性问题,提出了一种在惠斯通电桥中引入多晶硅的温度补偿方案。以单晶硅制备的高g值压阻式加速度计为模型,通过建立理论模型,分析了单晶硅压敏电阻的电阻率和压阻系数的温度特性。对传感器进行有限元仿真分析,仿真结果表明一阶频率为0.776 MHz,最大等效应力为44 MHz。通过对压敏电阻路径的线性分析,得到补偿前的灵敏度为0.349μV/g。对多晶硅电阻引入前后的输出电压进行理论分析,得到电阻系数比以及补偿前后传感器灵敏度随温度的变化关系。结果表明,补偿后的灵敏度漂移温度系数(Temperature Coefficient of Sensitivity drift,TCS)为6.8×10^(-4)(1/℃),与补偿前相比降低了两个数量级。

In this paper,a temperature compensation scheme with the addition of polysilicon to the Wheatstone bridge is proposed to solve the problem of piezoresistive sensors sensitivity nonlinearity when the ambient temperature changes.Taking the high-g piezoresistive accelerometer fabricated in monocrystalline silicon as a model,and the temperature characteristics of the resistivity and piezoresistive coefficient of the monocrystalline silicon varistor are analyzed by establishing theoretical model.The finite element simulation analysis of the sensor shows that the first-order frequency is 0.776 MHz and the maximum equivalent stress is 44 MHz.The sensitivity before compensation is 0.349μV/g by linear analysis of the piezoresistive path.Theory analysis of the output voltage before and after the introduction of the polysilicon resistor is performed to acquire the resistivity coefficient ratio and the variation of the sensor sensitivity with temperature before and after compensation.The results show that the temperature coefficient of sensitivity drift(TCS)after compensation is 6.8×10^(-4)(1/℃),which is two orders of magnitude lower than that before compensation.