Characteristics of MgxZn1-xO thin film bulk acoustic wave devices.
Characteristics of MgxZn1-xO thin film bulk acoustic wave devices.
复制标题
MgxZn1-xO薄膜体声波器件的特性。
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
A. Ballato
中科院分区：
文献类型：
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作者：
R. Wittstruck;X. Tong;N. Emanetoglu;P. Wu;Yimin Chen;Jun Zhu;S. Muthukumar;Yicheng Lu;A. Ballato
压电薄膜氧化锌（ZnO）及其三元合金镁锌氧化物（MgxZn 1-xO）在换能器、谐振器和滤波器等方面有着广泛的应用。本文提出了一种新的体声波结构，由Al/MgxZn 1-xO/n（+）-ZnO/r-sapphire组成，其中Al和n+型ZnO分别作为上电极和下电极。MgxZn 1-xO薄膜与衬底的外延关系与ZnO在r-Al 2 O3上的外延关系相同，MgxZn 1-xO薄膜的c轴位于生长平面内。这种关系促进了剪切体波传播，其提供了在液相介质中的感测，而没有在纵波模式BAW装置中发现的阻尼效应。体声波速度和机电耦合系数的MgxZn 1-xO可以定制通过改变镁的组合物，这提供了一种替代和补充的方法来调整体声波特性，通过改变压电薄膜的厚度。这为设计薄膜体声波器件的工作频率提供了灵活性。利用传输线模型分析了在特定结构中传播的具有两种声波模式的器件的频率响应。实测结果与仿真结果吻合较好。
Piezoelectric thin film zinc oxide (ZnO) and its ternary alloy magnesium zinc oxide (MgxZn1-xO) have broad applications in transducers, resonators, and filters. In this work, we present a new bulk acoustic wave (BAW) structure consisting of Al/MgxZn1-xO/n(+)-ZnO/r-sapphire, where Al and n+ type ZnO serve as the top and bottom electrode, respectively. The epitaxial MgxZn1-xO films have the same epitaxial relationships with the substrate as ZnO on r-Al2O3, resulting in the c-axis of the MgxZn1-xO being in the growth plane. This relationship promotes shear bulk wave propagation that affords sensing in liquid phase media without the dampening effects found in longitudinal wave mode BAW devices. The BAW velocity and electromechanical coupling coefficient of MgxZn1-xO can be tailored by varying the Mg composition, which provides an alternative and complementary method to adjust the BAW characteristics by changing the piezoelectric film thickness. This provides flexibility to design the operating frequencies of thin film bulk acoustic wave devices. Frequency responses of devices with two acoustic wave modes propagating in the specified structure are analyzed using a transmission line model. Measured results show good agreement with simulation.