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 |
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Title of host publication | 2019 IEEE International Ultrasonics Symposium, IUS 2019 |
Publisher | IEEE Institute of Electrical and Electronic Engineers |
Pages | 2489-2492 |
Number of pages | 4 |
ISBN (Electronic) | 978-1-7281-4596-9, 978-1-7281-4595-2 |
ISBN (Print) | 978-1-7281-4597-6 |
DOIs | |
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 |
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Country/Territory | United Kingdom |
City | Glasgow |
Period | 6/10/19 → 9/10/19 |
Keywords
- OtaNano