Design and Fabrication of Aluminum Nitride Piezoelectric Micromachined Ultrasonic Transducers for Air Flow Measurements

Cyril Karuthedath; Abhilash Thanniyil Sebastian; Jaakko Saarilahti; Teuvo Sillanpää; Tuomas Pensala

doi:10.1109/ULTSYM.2019.8925544

Design and Fabrication of Aluminum Nitride Piezoelectric Micromachined Ultrasonic Transducers for Air Flow Measurements

Cyril Karuthedath, Abhilash Thanniyil Sebastian, Jaakko Saarilahti, Teuvo Sillanpää, Tuomas Pensala

Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific

17 Citations (Scopus)

Abstract

Beam-drift based flow measurement technique requires frequency matched ultrasound transmitters and receivers for determining the flow rate. Aluminum nitride (AlN) piezoelectric micromachined ultrasonic transducers (PMUTs) suitable for such an application have been designed and fabricated. The bottom electrode is designed in such way that it reduces the stray capacitances, without degrading the piezoelectric properties of the AlN layer deposited on it. Frequency matching within a PMUT array and PMUTs fabricated across a wafer are challenging due to residual stress and membrane radius variations. A fabrication process to reduce the residual stress by optimizing the AlN layer deposition parameters, and membrane radius variations by optimizing Deep Reactive Ion Etching (DRIE) process, is developed in this work. The relative frequency variation (Δf*100/f) of the fabricated 7-element transmitter array is 0.5 %, and the variation between two receiver elements is 0.8%. Even though there is frequency variation across the wafer, PMUT transmitters and receivers within a reticle have matching frequencies and they can be utilized as transmitter-receiver pairs for flow measurement applications.

Original language	English
Title of host publication	2019 IEEE International Ultrasonics Symposium, IUS 2019
Publisher	IEEE Institute of Electrical and Electronic Engineers
Pages	2489-2492
ISBN (Electronic)	978-1-7281-4596-9, 978-1-7281-4595-2
ISBN (Print)	978-1-7281-4597-6
DOIs	https://doi.org/10.1109/ULTSYM.2019.8925544
Publication status	Published - 6 Oct 2019
MoE publication type	B3 Non-refereed article in conference proceedings
Event	2019 IEEE International Ultrasonics Symposium, IUS 2019 - Glasgow, United Kingdom Duration: 6 Oct 2019 → 9 Oct 2019

Conference

Conference	2019 IEEE International Ultrasonics Symposium, IUS 2019
Country/Territory	United Kingdom
City	Glasgow
Period	6/10/19 → 9/10/19

Funding

This work is part of the POSITION-II project funded by the ECSEL Joint Undertaking under grant number Ecsel-783132-Position-II-2017-IA. This study was financed in part by the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico - CNPq (grants 305610/2017-1 ) and Finep (grants 2210/2008).

Keywords

OtaNano

Access to Document

10.1109/ULTSYM.2019.8925544

Cite this

Karuthedath, C., Thanniyil Sebastian, A., Saarilahti, J., Sillanpää, T., & Pensala, T. (2019). Design and Fabrication of Aluminum Nitride Piezoelectric Micromachined Ultrasonic Transducers for Air Flow Measurements. In 2019 IEEE International Ultrasonics Symposium, IUS 2019 (pp. 2489-2492). Article 8925544 IEEE Institute of Electrical and Electronic Engineers. https://doi.org/10.1109/ULTSYM.2019.8925544

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title = "Design and Fabrication of Aluminum Nitride Piezoelectric Micromachined Ultrasonic Transducers for Air Flow Measurements",

abstract = "Beam-drift based flow measurement technique requires frequency matched ultrasound transmitters and receivers for determining the flow rate. Aluminum nitride (AlN) piezoelectric micromachined ultrasonic transducers (PMUTs) suitable for such an application have been designed and fabricated. The bottom electrode is designed in such way that it reduces the stray capacitances, without degrading the piezoelectric properties of the AlN layer deposited on it. Frequency matching within a PMUT array and PMUTs fabricated across a wafer are challenging due to residual stress and membrane radius variations. A fabrication process to reduce the residual stress by optimizing the AlN layer deposition parameters, and membrane radius variations by optimizing Deep Reactive Ion Etching (DRIE) process, is developed in this work. The relative frequency variation (Δf*100/f) of the fabricated 7-element transmitter array is 0.5 %, and the variation between two receiver elements is 0.8%. Even though there is frequency variation across the wafer, PMUT transmitters and receivers within a reticle have matching frequencies and they can be utilized as transmitter-receiver pairs for flow measurement applications.",

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author = "Cyril Karuthedath and {Thanniyil Sebastian}, Abhilash and Jaakko Saarilahti and Teuvo Sillanp{\"a}{\"a} and Tuomas Pensala",

note = "Publisher Copyright: {\textcopyright} 2019 IEEE.; 2019 IEEE International Ultrasonics Symposium, IUS 2019 ; Conference date: 06-10-2019 Through 09-10-2019",

year = "2019",

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doi = "10.1109/ULTSYM.2019.8925544",

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Karuthedath, C , Thanniyil Sebastian, A, Saarilahti, J, Sillanpää, T & Pensala, T 2019, Design and Fabrication of Aluminum Nitride Piezoelectric Micromachined Ultrasonic Transducers for Air Flow Measurements. in 2019 IEEE International Ultrasonics Symposium, IUS 2019., 8925544, IEEE Institute of Electrical and Electronic Engineers, pp. 2489-2492, 2019 IEEE International Ultrasonics Symposium, IUS 2019, Glasgow, United Kingdom, 6/10/19. https://doi.org/10.1109/ULTSYM.2019.8925544

Design and Fabrication of Aluminum Nitride Piezoelectric Micromachined Ultrasonic Transducers for Air Flow Measurements. / Karuthedath, Cyril ; Thanniyil Sebastian, Abhilash; Saarilahti, Jaakko et al.
2019 IEEE International Ultrasonics Symposium, IUS 2019. IEEE Institute of Electrical and Electronic Engineers, 2019. p. 2489-2492 8925544.

Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific

TY - GEN

T1 - Design and Fabrication of Aluminum Nitride Piezoelectric Micromachined Ultrasonic Transducers for Air Flow Measurements

AU - Karuthedath, Cyril

AU - Thanniyil Sebastian, Abhilash

AU - Saarilahti, Jaakko

AU - Sillanpää, Teuvo

AU - Pensala, Tuomas

PY - 2019/10/6

Y1 - 2019/10/6

N2 - Beam-drift based flow measurement technique requires frequency matched ultrasound transmitters and receivers for determining the flow rate. Aluminum nitride (AlN) piezoelectric micromachined ultrasonic transducers (PMUTs) suitable for such an application have been designed and fabricated. The bottom electrode is designed in such way that it reduces the stray capacitances, without degrading the piezoelectric properties of the AlN layer deposited on it. Frequency matching within a PMUT array and PMUTs fabricated across a wafer are challenging due to residual stress and membrane radius variations. A fabrication process to reduce the residual stress by optimizing the AlN layer deposition parameters, and membrane radius variations by optimizing Deep Reactive Ion Etching (DRIE) process, is developed in this work. The relative frequency variation (Δf*100/f) of the fabricated 7-element transmitter array is 0.5 %, and the variation between two receiver elements is 0.8%. Even though there is frequency variation across the wafer, PMUT transmitters and receivers within a reticle have matching frequencies and they can be utilized as transmitter-receiver pairs for flow measurement applications.

AB - Beam-drift based flow measurement technique requires frequency matched ultrasound transmitters and receivers for determining the flow rate. Aluminum nitride (AlN) piezoelectric micromachined ultrasonic transducers (PMUTs) suitable for such an application have been designed and fabricated. The bottom electrode is designed in such way that it reduces the stray capacitances, without degrading the piezoelectric properties of the AlN layer deposited on it. Frequency matching within a PMUT array and PMUTs fabricated across a wafer are challenging due to residual stress and membrane radius variations. A fabrication process to reduce the residual stress by optimizing the AlN layer deposition parameters, and membrane radius variations by optimizing Deep Reactive Ion Etching (DRIE) process, is developed in this work. The relative frequency variation (Δf*100/f) of the fabricated 7-element transmitter array is 0.5 %, and the variation between two receiver elements is 0.8%. Even though there is frequency variation across the wafer, PMUT transmitters and receivers within a reticle have matching frequencies and they can be utilized as transmitter-receiver pairs for flow measurement applications.

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SN - 978-1-7281-4597-6

SP - 2489

EP - 2492

BT - 2019 IEEE International Ultrasonics Symposium, IUS 2019

PB - IEEE Institute of Electrical and Electronic Engineers

T2 - 2019 IEEE International Ultrasonics Symposium, IUS 2019

Y2 - 6 October 2019 through 9 October 2019

ER -

Karuthedath C , Thanniyil Sebastian A, Saarilahti J, Sillanpää T , Pensala T. Design and Fabrication of Aluminum Nitride Piezoelectric Micromachined Ultrasonic Transducers for Air Flow Measurements. In 2019 IEEE International Ultrasonics Symposium, IUS 2019. IEEE Institute of Electrical and Electronic Engineers. 2019. p. 2489-2492. 8925544 doi: 10.1109/ULTSYM.2019.8925544

Design and Fabrication of Aluminum Nitride Piezoelectric Micromachined Ultrasonic Transducers for Air Flow Measurements

Abstract

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Cite this

Design and Fabrication of Aluminum Nitride Piezoelectric Micromachined Ultrasonic Transducers for Air Flow Measurements

Abstract

Conference

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Keywords

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OtaNano

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