提出并制备了基于聚酰亚胺柔性衬底的声表面波(SAW)器件。在柔性聚酰亚胺衬底上低温反应磁控溅射沉积了ZnO压电薄膜; 采用X射线衍射仪, 扫描电子显微镜, 原子力显微镜等设备对ZnO薄膜进行了检测, 结果表明: ZnO薄膜晶粒呈柱状生长并且(002)择优取向, 膜粗糙度小于9 nm, 适合制作压电器件。在柔性衬底上制备了基于ZnO压电薄膜的SAW器件, 该器件表现出良好的谐振性能。采用矢量网络分析仪检测器件的传输曲线, 实验结果与仿真结果具有很好的一致性。随着波长减小, 谐振频率和相速度增加, 当ZnO厚度为4 μm, 波长为8 μm时, 器件的谐振频率为268 MHz, 相速度为2 144m/s, 机电耦合系数为1.1 %; 当ZnO厚度增加时, 此叠层结构的声表面器件的叠层声速也增加。

Surface Acoustic Wave (SAW) devices on flexible polyimide substrates were developed. The ZnO piezoelectric layers were deposited on a flexible polyimide substrate by low temperature reactive magnetron sputtering, then the layers were characterized by the X-ray Diffraction (XRD), Sanning Electron Microscope(SEM), and the Atomic Force Microscope. The results show that ZnO layers with columnar structures have (002) crystal orientation and lower layer roughness(less than 9 nm), and they are suitable for fabrication of piezoelectric devices. The SAW device based on the ZnO piezoelectric layers were fabricated on a flexible polyimide substrate, and it could offer excellent resonance characteristics. A vector network analyzer was used detect the transmission curve, and results show that the resonance frequency and phase velocity increase with decreasing wavelength, and the experimental results are in good agreement with the simulated results. When the thickness and wavelength of the ZnO layer are 4 micron, and 8 micron, respectively, the device has its resonant frequency of 268 MHz, acoustic phase velocity of 2 144 m/s and the electromechanical coupling coefficent of 1.1 %. Moreover, the acoustic velocity in the ZnO layer also increases with the increase of the ZnO thickness.