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

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 Si(3)N(4) as a passive la...

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Autores principales: Ledesma, Eyglis, Zamora, Ivan, Uranga, Arantxa, Torres, Francesc, Barniol, Núria
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8705788/
https://www.ncbi.nlm.nih.gov/pubmed/34960541
http://dx.doi.org/10.3390/s21248447
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author Ledesma, Eyglis
Zamora, Ivan
Uranga, Arantxa
Torres, Francesc
Barniol, Núria
author_facet Ledesma, Eyglis
Zamora, Ivan
Uranga, Arantxa
Torres, Francesc
Barniol, Núria
author_sort Ledesma, Eyglis
collection PubMed
description 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 Si(3)N(4) 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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spelling pubmed-87057882021-12-25 Enhancing AlN PMUTs’ Acoustic Responsivity within a MEMS-on-CMOS Process Ledesma, Eyglis Zamora, Ivan Uranga, Arantxa Torres, Francesc Barniol, Núria Sensors (Basel) Article 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 Si(3)N(4) 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. MDPI 2021-12-17 /pmc/articles/PMC8705788/ /pubmed/34960541 http://dx.doi.org/10.3390/s21248447 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Ledesma, Eyglis
Zamora, Ivan
Uranga, Arantxa
Torres, Francesc
Barniol, Núria
Enhancing AlN PMUTs’ Acoustic Responsivity within a MEMS-on-CMOS Process
title Enhancing AlN PMUTs’ Acoustic Responsivity within a MEMS-on-CMOS Process
title_full Enhancing AlN PMUTs’ Acoustic Responsivity within a MEMS-on-CMOS Process
title_fullStr Enhancing AlN PMUTs’ Acoustic Responsivity within a MEMS-on-CMOS Process
title_full_unstemmed Enhancing AlN PMUTs’ Acoustic Responsivity within a MEMS-on-CMOS Process
title_short Enhancing AlN PMUTs’ Acoustic Responsivity within a MEMS-on-CMOS Process
title_sort enhancing aln pmuts’ acoustic responsivity within a mems-on-cmos process
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8705788/
https://www.ncbi.nlm.nih.gov/pubmed/34960541
http://dx.doi.org/10.3390/s21248447
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