Multielement Ring Array Based on Minute Size PMUTs for High Acoustic Pressure and Tunable Focus Depth

Ledesma, Eyglis; Zamora, Iván; Uranga, A.; Barniol, N.

doi:10.3390/s21144786

Cited by 4 publications

(2 citation statements)

References 31 publications

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“…Frequency and hydrophone micrometric positioning over the PMUT were manually tuned to maximize the receiving signal. Note that for liquid operation, the added mass loading effect should be considered [25], which will lower the resonance frequency from the 4-5 MHz found in air to the 1-2 MHz range as expected from the results shown in Figure 3.…”

Section: Acoustic Characterizationmentioning

confidence: 58%

Enhancing AlN PMUTs’ Acoustic Responsivity within a MEMS-on-CMOS Process

Ledesma

Zamora

Uranga

et al. 2021

Sensors

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In this paper, guidelines for the optimization of piezoelectrical micromachined ultrasound transducers (PMUTs) monolithically integrated over a CMOS technology are developed. Higher acoustic pressure is produced by PMUTs with a thin layer of AlN piezoelectrical material and Si3N4 as a passive layer, as is studied here with finite element modeling (FEM) simulations and experimental characterization. Due to the thin layers used, parameters such as residual stress become relevant as they produce a buckled structure. It has been reported that the buckling of the membrane due to residual stress, in general, reduces the coupling factor and consequently degrades the efficiency of the acoustic pressure production. In this paper, we show that this buckling can be beneficial and that the fabricated PMUTs exhibit enhanced performance depending on the placement of the electrodes. This behavior was demonstrated experimentally and through FEM. The acoustic characterization of the fabricated PMUTs shows the enhancement of the PMUT performance as a transmitter (with 5 kPa V−1 surface pressure for a single PMUT) and as a receiver (12.5 V MPa−1) in comparison with previously reported devices using the same MEMS-on-CMOS technology as well as state-of-the-art devices.

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Section: Acoustic Characterizationmentioning

confidence: 58%

Enhancing AlN PMUTs’ Acoustic Responsivity within a MEMS-on-CMOS Process

Ledesma

Zamora

Uranga

et al. 2021

Sensors

Self Cite

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“…The presented PMUT is a two-port device fabricated using the MEMS-on-CMOS process of Silterra 24 , 27 . As shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

Single-cell system using monolithic PMUTs-on-CMOS to monitor fluid hydrodynamic properties

et al. 2022

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In this work, a single cell capable of monitoring fluid density, viscosity, sound velocity, and compressibility with a compact and small design is presented. The fluid measurement system is formed by a two-port AlScN piezoelectric micromachined ultrasonic transducer (PMUT) with an 80 μm length monolithically fabricated with a 130 nm complementary metal-oxide semiconductor (CMOS) process. The electrode configuration allows the entire system to be implemented in a single device, where one electrode is used as an input and the other as an output. Experimental verification was carried out by exploiting the features of piezoelectric devices such as resonators and acoustic transducers, where a frequency shift and amplitude variation are expected because of a change in density and viscosity. A sensitivity of 482 ± 14 Hz/kg/m3 demonstrates the potential of the system compared to other dual-electrode PMUTs. In addition, according to the acoustic measurement, the sound velocity, fluid compressibility, and viscosity coefficient can be extracted, which, to the best of our knowledge, is novel in these PMUT systems.

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