Design, fabrication and reliability study of piezoelectric ZnO based structure for development of MEMS acoustic sensor
Design, fabrication and reliability study of piezoelectric ZnO based structure for development of MEMS acoustic sensor
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DOI：
10.1007/s00542-019-04524-x
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发表时间：
2019-12-01
影响因子：
2.1
通讯作者：
Yadav, R. P.
中科院分区：
文献类型：
--
作者：
Kumar, Ashish;Prasad, Mahanth;Yadav, R. P.
本文报道了一种基于压电氧化锌 (ZnO) 的声学传感器，适用于音频和气动声学应用，具有高声压级 (SPL) 和宽带宽。使用基于有限元法 (FEM) 的 MEMS-CAD 工具 Coventorware 对所提出的结构进行了模拟，并优化了隔膜的尺寸，以实现 100-180 dB 声压级 (SPL) 的大动态范围和大带宽 (22 kHz)。模拟结构的共振频率为67 kHz。选择了优化的结构尺寸并制造了该结构。隔膜结构是使用体微机械湿法蚀刻工艺释放的。采用射频 (RF) 溅射技术沉积了 1.71 μm 的 ZnO 薄膜，并使用 X 射线粉末衍射 (XRD) 和原子力显微镜 (AFM) 进行了表征。使用激光多普勒振动计 (LDV) 测量所制造器件的谐振频率，结果为 65 kHz。测量了所制作器件的实验灵敏度，结果为80μV/Pa。对装配式结构进行了可靠性测试。发现可以通过铝 (Al) 和沉积的 ZnO 边缘的最大电流为 2.69 A，而不会造成任何损坏。测量了所制造器件参数的电特性，例如电容、损耗（tanδ），并研究了频率变化对两者的影响。
This paper reports a piezoelectric zinc oxide (ZnO) based acoustic sensor for high sound pressure level (SPL) with wide bandwidth for audio and aeroacoustic applications. The proposed structure has been simulated using finite element method (FEM) based MEMS-CAD tool Coventorware and optimized the dimensions of the diaphragm for a large dynamic range of 100-180 dB sound pressure level (SPL) and large bandwidth (22 kHz). The resonant frequency of the simulated structure is 67 kHz. Optimized structure dimensions have been chosen and fabricated the structure. The diaphragm structure has been released using bulk micromachining wet etching process. The ZnO thin film of 1.71 mu m has been deposited using radio frequency (RF) sputtering technique and characterized using X-ray powder diffraction (XRD) and atomic force microscopy (AFM). The resonant frequency of the fabricated device is measured using laser doppler vibrometer (LDV) and found to be 65 kHz. The experimental sensitivity of the fabricated device is measured and is found to be 80 mu V/Pa. The reliability testing of the fabricated structure was performed. The maximum current that can be passed across aluminum (Al) and deposited ZnO edge was found to be 2.69 A without any damage. The electrical characterization such as capacitance, loss (tan delta) of fabricated device parameters were measured and the effects of frequency variation on both were also studied.