This study presents the fabrication and characterization of a piezoelectric micromachined ultrasonic transducer (pMUT; radius: 40 μm) using a patterned aluminum nitride (AlN) thin film as the active piezoelectric material. A 20 × 20 array of pMUTs using a 1 μm thick AlN thin film was designed and fabricated on a 2 × 2 mm² footprint for a high fill factor. Based on the electrical impedance and phase of the pMUT array, the electromechanical coefficient was ~1.7% at the average resonant frequency of 2.82 MHz in air. Dynamic displacement of the pMUT surface was characterized by scanning laser Doppler vibrometry. The pressure output while immersed in water was 19.79 kPa when calculated based on the peak displacement at the resonant frequency. The proposed AlN pMUT array has potential applications in biomedical sensing for healthcare, medical imaging, and biometrics.

中文翻译：

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基于图案化氮化铝薄膜的高密度压电微机械超声换能器阵列的研制。

这项研究提出了使用图案化的氮化铝（AlN）薄膜作为活性压电材料的压电微机械超声换能器（pMUT;半径：40μm）的制造和表征。设计并使用2×2 mm ²的面积设计了一个使用1μm厚的AlN薄膜的20×20 pMUT阵列。占位面积高的填充因子。根据pMUT阵列的电阻抗和相位，在空气中的平均共振频率为2.82 MHz时，机电系数约为1.7％。通过扫描激光多普勒振动法表征了pMUT表面的动态位移。当基于共振频率下的峰值位移计算时，浸入水中时的压力输出为19.79 kPa。拟议的AlN pMUT阵列在医疗保健，医学成像和生物识别的生物医学传感方面具有潜在的应用。