異種圧電材料を集積した革新的超音波ＭＥＭＳデバイスおよび高性能超音波撮像器の創出

在2022财年，进展主要包括3个部分1.模拟了双压电层pMUT组合的最佳结构。对用于发射层和接收层的材料进行了模拟。基于仿真结果，我们发现双层pMUT的性能大约是常规型pMUT的2.3~2.8倍。考虑到制作的可行性，设计了制作工艺。研究了双压电层异质集成的沉积条件。在模拟结果的基础上，通过选择合适的中间电极，首次实现了单晶AlN在PMN-PT薄膜上的集成。接下来，我们探索了在AlN薄膜上沉积纯钙钛矿相PZT的条件。结果，堆叠在一起的异质薄膜的集成成功了。制备了双层pMUT，并对其进行了表征。制备了AlN/PMN-PT型pMUT和PZT/AlN型pMUT。通过在薄膜上施加驱动电压，确认了所有压电层的驱动。到目前为止，对器件的谐振频率和传输性能进行了表征。现在我们正在进行灵敏度测量的实验。

In FY2022, the progress mainly includes 3 parts.1. The best structure for a dual-piezo-layer pMUT combination was simulated. The material used for the transmitting layer and receiving layer was simulated. Based on the simulation result, we found that the performance of dual-layer-pMUT was about 2.3 to 2.8 times higher than the conventional type pMUT. Considering the fabrication feasibility, the fabrication process was designed.2. The deposition condition for hetero-integration of the dual piezoelectric layer was researched. Based on the simulation result, we first realized the integration of single crystal AlN stacked on PMN-PT thin film by selecting suitable intermediate electrodes. Next, we explored the deposition condition for pure-perovskite-phase PZT stacked on AlN thin film. As a result, the integration of heterogeneous thin films stacked on top of each other succeeded3. The dual-layer pMUT was fabricated and characterized. We fabricated AlN/PMN-PT type pMUT and PZT/AlN type pMUT. The actuation of all the piezoelectric layers was confirmed by applying driving voltage on the thin film. Up to now, the resonant frequency and transmitting performance of the devices were characterized. Now we are setting up experiments for sensitivity measuring.