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，进展主要包括三个部分。模拟了双压电层pMUT组合的最佳结构。模拟了发射层和接收层所用的材料。基于仿真结果，我们发现双层pMUT的性能大约是常规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积分的沉积条件。在模拟结果的基础上，通过选择合适的中间电极，首次实现了在PMN-PT薄膜上堆叠AlN单晶的集成。接下来，我们探索了纯钙钛矿相PZT叠加在AlN薄膜上的沉积条件。结果，异质薄膜相互叠加的集成成功了3。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，证实了所有压电层的驱动。到目前为止，对器件的谐振频率和发射性能进行了表征。现在我们正在进行灵敏度测量实验。

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.