电容式微超声波换能器的设计与电容值测试

Design of capacitance micro ultrasonic transducer and test of capacitance value

该文通过对电容式微超声波换能器电容值测试分析了传感器的电容性能。该文设计的电容式微超声波换能器是由电容阵列组成的,主要是利用电容的改变来实现能量的转换。它是基于硅硅键合技术的微机电系统的电容式超声传感器,由其制作的传感器误差小、工艺流程简单且能进行量产。利用E4990A阻抗分析仪测试传感器电容值在工作电压下随频率的变化,得出频率为400 k Hz时电容值为617.67 p F。并且利用该仪器对传感器进行C-V测试分析而得出其电容的实际值与理论值的误差仅为1.6%。所得结果为对传感器进行理论计算提供了重要支撑,并且为后续转换电路的设计提供了数据支撑。

In this letter,we analyzed the capacitance performance of the sensor through measuring the capacitance of a capacitance-micro-ultrasonic-transducer.The capacitance-micro-ultrasonic-transducer we designed is composed of capacitance array,which mainly uses the change of capacitance to realize the conversion of energy.It is a capacitive ultrasonic sensor based on Si-Si bonding technology for MEMS.Further,the sensor has a small error and can be mass-produced due to it’s simple process.The E4990A impedance analyzer is used to test the change of the capacitance value of the sensor with the frequency under the working voltage,and the capacitance value is 617.67 pF when the frequency is 400 kHz.In addition,we obtain that the error of sensor’s capacitance between actual and theoretical value is only 1.6%by test and analyze the sensor’s C-V characteristics with our instrument.The results provide an important support for the theoretical calculation of the sensor,and provide data support for the design of the subsequent conversion circuit.