Fabrication and characterization of row-column addressed pMUT array with monocrystalline PZT thin film toward creating ultrasonic imager
Fabrication and characterization of row-column addressed pMUT array with monocrystalline PZT thin film toward creating ultrasonic imager
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DOI：
10.1016/j.sna.2022.113666
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发表时间：
2022-06-09
影响因子：
4.6
通讯作者：
Tanaka, Shuji
中科院分区：
文献类型：
--
作者：
Liu, Ziyi;Yoshida, Shinya;Tanaka, Shuji
在本研究中，我们基于单晶PZT薄膜制备了一种行列式寻址二维压电微机械超声换能器(PMUT)阵列，并展示了其作为超声成像器的应用。首先，我们将岛形设计作为一个单独的元素进行优化，然后开发了基于绝缘聚合物图案边缘形状控制的制造工艺。结果成功地制作出了直径为70微米、节距为120微米的最大阵元数为372个的六边形阵列。空气中的谐振频率约为5.4 MHz，位移灵敏度约为175 nm/V，品质因数约为175。该阵列显示出低串扰。未寻址元件的激励小于寻址元件的10%。此外，谐振频率和位移灵敏度的偏差分别只有2%和15%。在此基础上，采用5列最小单元阵评价了FC-70介质的基本声学性能。同时，通过施加延迟驱动电压，实现了聚焦超声爆破波的发射波束形成。最后，通过对金属物体进行机械扫描，实现了对金属物体的超声成像。
In this study, we fabricated a row-column addressed 2-dimensional piezoelectric micromachined ultrasonic transducer (pMUT) array based on the monocrystalline Pb(Zr, Ti)O3 (Mono PZT)-based thin film, and demonstrated its application as the ultrasound imager. At first, we optimized the island-shaped design as an individual element, and then developed the fabrication process based on the control of the edge shape of an insulative polymer pattern. As a result, the hexagonally arranged arrays with 372 elements at the maximum were fabricated successfully, of which the diameter and pitch were 70 mu m and 120 mu m, respectively. The resonance frequency, displacement sensitivity, and quality factor in air measured approximately 5.4 MHz, 175 nm/V and 175, respectively. This array exhibited low crosstalk. The actuation of the unaddressed element was less than 10 % of that of the addressed one. In addition, the deviations on the resonance frequencies and displacement sensitivities were as small as only 2 % and 15 %, respectively. Then, the basic acoustic performance in a medium FC-70 was evaluated by using the minimum unit array composed of 5 columns. Also, the transmitting beamforming of a focused ultrasonic burst wave was done by applying driving voltages with a time delay. Finally, an ultrasonic imaging for a metallic object was demonstrated by mechanically scanning the object.