Kang Dong-Chan, Kim Jeong-Nyeon, Park Ik-Keun
Graduate School of Nano IT Design Fusion, Seoul National University of Science and Technology, 232, Gongneung-ro, Nowon-gu, Seoul 01811, Korea.
Ginzton Laboratory, Stanford University, Stanford, CA 94305, USA.
Materials (Basel). 2021 Nov 14;14(22):6870. doi: 10.3390/ma14226870.
In the study, an acoustic sensor for a high-resolution acoustic microscope was fabricated using zinc oxide (ZnO) piezoelectric ceramics. The c-cut sapphire was processed into a lens shape to deposit a ZnO film using radio frequency (RF) magnetron sputtering, and an upper and a lower electrode were deposited using E-beam evaporation. The electrode was a Au thin film, and a Ti thin film was used as an adhesion layer. The surface microstructure of the ZnO film was observed using a scanning electron microscope (SEM), the thickness of the film was measured using a focused ion beam (FIB) for piezoelectric ceramics deposited on the sapphire wafer, and the thickness of ZnO was measured to be 4.87 μm. As a result of analyzing the crystal growth plane using X-ray diffraction (XRD) analysis, it was confirmed that the piezoelectric characteristics were grown to the (0002) plane. The sensor fabricated in this study had a center frequency of 352 MHz. The bandwidth indicates the range of upper (375 MHz) and lower (328 MHz) frequencies at the -6 dB level of the center frequency. As a result of image analysis using the resolution chart, the resolution was about 1 μm.
在该研究中，使用氧化锌（ZnO）压电陶瓷制造了一种用于高分辨率声学显微镜的声学传感器。将c切割蓝宝石加工成透镜形状，以便使用射频（RF）磁控溅射沉积ZnO薄膜，并使用电子束蒸发沉积上下电极。电极是金薄膜，钛薄膜用作粘附层。使用扫描电子显微镜（SEM）观察ZnO薄膜的表面微观结构，对于沉积在蓝宝石晶片上的压电陶瓷，使用聚焦离子束（FIB）测量薄膜的厚度，测得ZnO的厚度为4.87μm。通过X射线衍射（XRD）分析晶体生长平面的结果表明，压电特性沿（0002）平面生长。本研究中制造的传感器中心频率为352 MHz。带宽表示中心频率-6 dB水平下的上限频率（375 MHz）和下限频率（328 MHz）范围。使用分辨率测试图进行图像分析的结果表明，分辨率约为1μm。
