A Comparative Study of Si3N4 and Al2O3 as Dielectric Materials for Pre-Charged Collapse-Mode CMUTs

Conference paper (2023)

Authors

M. Saccher Electronic Components, Technology and Materials - EEMCS
Rob van Schaijk Philips
A. Rashidi Bio-Electronics - EEMCS
Vasiliki Giagka Fraunhofer Institute for Reliability and Microintegration IZM, Bio-Electronics - EEMCS
Alessandro S. Savoia University of Roma Tre
R. Dekker Electronic Components, Technology and Materials - EEMCS , Philips
Research Group
Electronic Components, Technology and Materials (EEMCS) (TU Delft)
Copyright: © 2023 M. Saccher, Rob van Schaijk, Shinnosuke Kawasaki, Johan H. Klootwijk, A. Rashidi, Vasiliki Giagka, Alessandro Stuart Savoia, R. Dekker
DOI
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https://doi.org/10.1109/IUS51837.2023.10307389
Pre-charged CMUT Zero-bias transducers Capacitive Micromachined Ultrasound Transducer Ultrasonic power transfer
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Published Date

2023

Language

English

Reuse Rights

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Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Microelectronics

Research Group

Electronic Components, Technology and Materials

Abstract

Capacitive Micromachined Ultrasound Transducers (CMUTs) have many advantages compared to other ultrasonic transducer technologies, especially for implantable devices. However, they require a high bias voltage for efficient operation. To eliminate the need for an external bias voltage, a charge storage layer can be embedded in the dielectric. This study aims to compare the performance of Si 3 N 4 and Al 2 O 3 when used as a charge storage layer. By measuring the shift in the C-V curve, Si 3 N 4 exhibits a larger shift than Al 2 O 3 , indicating a better charge-trapping capability. When using the pre-charged CMUTs as power receivers, the Si 3 N 4 version harvested up to 80 mW -only a few mW more than the Al 2 O 3 - with an efficiency of about 50 %. Accelerated Lifetime Tests predict a lifetime of about 7.8 and 1.2 years for Si 3 N 4 and Al 2 O 3 respectively.