硅微压电超声换能器的设计与制作

Development and Analysis of Piezoelectric Micro-Machined Ultrasonic Transducers in Silicon Substrate

介绍了一种用ZnO薄膜作为压电层的硅微压电式超声换能器(PMUT).该硅微压电换能器的振动基膜采用LPCVD制作的氮化硅薄膜和PECVD制作的二氧化硅形成的复合振动膜结构.文中运用有限元方法对该硅微压电换能器的结构进行了模拟和计算,并进行了预应力对硅微换能器共振频率的影响的分析.实验测得硅微压电式换能器的共振频率为71.36kHz.本文还使用该硅微超声换能器在油中进行了初步的共振频率点收发信号的实验,接收实验测得信号峰峰值为9mV左右,发射实验标准水听器接收信号峰峰值为0.8mV左右.

This paper presents the design, analysis and fabrication of piezoelectric micro-machined ultrasonic transducers （PMUT） widely used in acoustic imaging field. The transducer consists of piezoelectric ZnO thin film and the composite membrane composed of Si3N4 and LTO. The simulation of the micro-machined piezoelectric transducer has been made by the FEM method, which includes the analysis of the pre-stress effect on the resonant frequency of the transducers. Experiment results indicate the resonant frequency of the micro-machined piezoelectric transducer is 71 kHz. The micro-machined piezoelectric transducer is primarily tested as the transducer and the receiver at the resonant frequency in the oil tank. Its received signal is about 9 mV. When it is used as the transmitter, the received signal of standard hydrophone is about 0. 8 mV.