AlN-on-SOI platform-based micro-machined hydrophone

Xu, Jinghui; Zhang, Xiaolin; Fernando, Saman; Chai, Kevin Tshun Chuan; Gu, Yuandong

doi:10.1063/1.4959078

Cited by 44 publications

(24 citation statements)

References 15 publications

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“…AlN PMUT arrays are fabricated on a double-side polishing SOI wafer with customized cavities [24,25]. In order to obtain high orientation and good roughness, a 20-nm AlN seed layer is first deposited on the SOI substrate.…”

Section: Methodsmentioning

confidence: 99%

3D FEM Analysis of High-Frequency AlN-Based PMUT Arrays on Cavity SOI

Liu

Wang

et al. 2019

Sensors

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This paper presents three-dimensional (3D) models of high-frequency piezoelectric micromachined ultrasonic transducers (PMUTs) based on the finite element method (FEM). These models are verified with fabricated aluminum nitride (AlN)-based PMUT arrays. The 3D numerical model consists of a sandwiched piezoelectric structure, a silicon passive layer, and a silicon substrate with a cavity. Two types of parameters are simulated with periodic boundary conditions: (1) the resonant frequencies and mode shapes of PMUT, and (2) the electrical impedance and acoustic field of PMUT loaded with air and water. The resonant frequencies and mode shapes of an electrically connected PMUT array are obtained with a laser Doppler vibrometer (LDV). The first resonant frequency difference between 3D FEM simulation and the measurement for a 16-MHz PMUT is reasonably within 6%, which is just one-third of that between the analytical method and the measurement. The electrical impedance of the PMUT array measured in air and water is consistent with the simulation results. The 3D model is suitable for predicting electrical and acoustic performance and, thus, optimizing the structure of high-frequency PMUTs. It also has good potential to analyze the transmission and reception performances of a PMUT array for future compact ultrasonic systems.

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Section: Methodsmentioning

confidence: 99%

3D FEM Analysis of High-Frequency AlN-Based PMUT Arrays on Cavity SOI

Liu

Wang

et al. 2019

Sensors

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“…They also developed a micromachined hydrophone employing a piezoelectric body on the gate of a field-effect transistor 9 . Xu et al 10 presented a kind of AlN-on-SOI micromachined hydrophone with high sensitivity. However, these piezoelectric hydrophones were nondirectional and could bear only low hydrostatic pressure due to the sealed membrane structure.…”

Section: Introductionmentioning

confidence: 99%

Design and implementation of a jellyfish otolith-inspired MEMS vector hydrophone for low-frequency detection

et al. 2021

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Detecting low-frequency underwater acoustic signals can be a challenge for marine applications. Inspired by the notably strong response of the auditory organs of pectis jellyfish to ultralow frequencies, a kind of otolith-inspired vector hydrophone (OVH) is developed, enabled by hollow buoyant spheres atop cilia. Full parametric analysis is performed to optimize the cilium structure in order to balance the resonance frequency and sensitivity. After the structural parameters of the OVH are determined, the stress distributions of various vector hydrophones are simulated and analyzed. The shock resistance of the OVH is also investigated. Finally, the OVH is fabricated and calibrated. The receiving sensitivity of the OVH is measured to be as high as −202.1 dB@100 Hz (0 dB@1 V/μPa), and the average equivalent pressure sensitivity over the frequency range of interest of the OVH reaches −173.8 dB when the frequency ranges from 20 to 200 Hz. The 3 dB polar width of the directivity pattern for the OVH is measured as 87°. Moreover, the OVH is demonstrated to operate under 10 MPa hydrostatic pressure. These results show that the OVH is promising in low-frequency underwater acoustic detection.

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“…So far, the sensors made according to its structure and principle include flow sensors, hydrophones, tactile sensors, vibration sensors, and gravity sensors [43]. Among them, vector turbulence sensors can be developed from the core sensitive structure of vector hydrophones to obtain the vector information of the underwater acoustic signals [44]- [46]. There are two reasons for that: Firstly, the sensitivity mechanism of certain hydrophones is applicable to the hydraulic excitation, whereas it depends on the specifications of their sensitive structures.…”

Section: Introductionmentioning

confidence: 99%

Vector High-Resolution Marine Turbulence Sensor Based on a MEMS Bionic Cilium-Shaped Structure

et al. 2021

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Studies show that the detection of vector turbulence characteristics is of significant importance for further cognition of the marine turbulence mechanism. However, a succedent research process may be impeded by the detection dimensionality of existing marine turbulence sensors. In the present study, a vector high-resolution turbulence sensor (VHTS) is designed from a cilium-shaped structure. The designed VHTS is based on the bionic principle and the MEMS manufacturing technology. A systematic investigation is conducted to improve the VHTS and meet the stringent requirements in marine applications. The measuring sensitivity and natural frequency of the VHTS are balanced by performing theoretical analyses and numerical simulations. Moreover, the vector detection mechanism of the sensitive microstructure is analyzed. Then the designed VHTS is fabricated and encapsulated elaborately by MEMS processes and three-dimensional heterogeneous integration. The calibration experiments show that the sensitivity of the designed VHTS is up to 2.68 × 10 −2 (V•m•s 2 )/kg. The vector verification testing exhibits the excellent orientation behaviors of the designed VHTS, indicating the feasibility of the VHTS to realize the detection of vector turbulence characteristics. The present study may provide a new opportunity for accurate observation and mechanism cognition of turbulence.

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AlN-on-SOI platform-based micro-machined hydrophone

Cited by 44 publications

References 15 publications

3D FEM Analysis of High-Frequency AlN-Based PMUT Arrays on Cavity SOI

3D FEM Analysis of High-Frequency AlN-Based PMUT Arrays on Cavity SOI

Design and implementation of a jellyfish otolith-inspired MEMS vector hydrophone for low-frequency detection

Vector High-Resolution Marine Turbulence Sensor Based on a MEMS Bionic Cilium-Shaped Structure

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