基于PMN-PT厚膜的高频超声换能器阵列研究

In order to meet the requirement of ultrasound imaging of skins, eyes, blood vessels and small animals' organs, it is necessary to bulid high frequency (>50MHz)ultrasound transducer and array. Based on our previous work, in this project，PMN-PT thick film will be used to take the place of PZT thick film to be the piezoelectric layer in ultrasound transdcuer, and related researches on fundamental theoretical,experimental analysis and integrated process will be conducted to enhance the performace of the device. The scope of the main work includes : to prepare PMN-PT thick film on Pt/Ti/SiO2/Si substrate using sol-gel composite method; to analyze the mechanism of the lift-off process of PMN-PT thick film from the Si substrate in the film transfer expriement; to find out the key factor to influent the performance of the PMN-PT thick film according to the result of comparative research on properties of the film with and without substrate; based on theoretical calculation, accoustic field simulation and study on micromachining etching of PMN-PT thick film,to overcome the difficulty in array element coupling of high frequency device; to fabricate high frequency (>50MHz) ultrasound linear array with not less than 32 elements, the bandwidth at -6dB more than 50%,the insertion loss better than -25dB and cross talk less than -30dB.The success of this project will be of great significance for frontier scientific research on thick film functional device and high frequency ultrasound technology.

为了满足皮肤、眼睛、血管以及小动物器官的超声成像的需要，必须研制高频（>50MHz）超声换能器及阵列。本项目拟在前期工作基础之上，采用PMN-PT厚膜代替PZT厚膜作为器件的压电层，并开展相关基础理论、实验分析及集成工艺的研究，以提高器件性能。主要研究内容包括：用复合溶胶凝胶法在Si基衬底(Pt/Ti/SiO2/Si)上制备PMN-PT厚膜；通过PMN-PT厚膜转移的实验研究，分析厚膜与Si衬底的分离机理；根据有衬底与无衬底PMN-PT厚膜的性能对比研究，揭示影响厚膜性能的关键因素；通过理论计算、声场仿真以及PMN-PT厚膜微加工刻蚀研究，解决高频器件阵元间的耦合问题；研制出阵元数不少32、-6dB带宽大于50%、插入损耗优于-25dB、阵元间串扰小于-30dB的高频（>50MHz）超声换能器线型阵列。本项目的完成对厚膜功能器件和高频超声技术等前沿科学问题的深入研究有着重要的意义。

为了满足皮肤、眼睛、血管以及小动物器官的超声成像的需要，必须研制高频（>50MHz）超声换能器及阵列。本项目拟在前期工作基础之上，采用PMN-PT 厚膜代替PZT厚膜作为器件的压电层，并开展相关基础理论、实验分析及集成工艺的研究，以提高器件性能。主要研究内容包括：用复合溶胶凝胶法在Si 基衬底(Pt/Ti/SiO2/Si)上制备PMN-PT 厚膜；通过PMN-PT 厚膜转移的实验研究，分析厚膜与Si 衬底的分离机理；根据有衬底与无衬底PMN-PT 厚膜的性能对比研究，揭示影响厚膜性能的关键因素；通过理论计算、声场仿真以及PMN-PT 厚膜微加工刻蚀研究，解决高频器件阵元间的耦合问题；研制出阵元数不少32、-6dB 带宽大于50%、插入损耗优于-25dB、阵元间串扰小于-30dB 的高频（>50MHz）超声换能器线型阵列。本项目的完成对厚膜功能器件和高频超声技术等前沿科学问题的深入研究有着重要的意义。