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 Si3N4 and Al2O3 when used as a charge storage layer. By measuring the shift in the C-V curve, Si3N4 exhibits a larger shift than Al2O3, indicating a better charge-trapping capability. When using the pre-charged CMUTs as power receivers, the Si3N4 version harvested up to 80 mW -only a few mW more than the Al2O3 - with an efficiency of about 50 %. Accelerated Lifetime Tests predict a lifetime of about 7.8 and 1.2 years for Si3N4 and Al2O3 respectively.
Saccher, M., Van Schaijk, R., Kawasaki, S., Klootwijk, J.H., Rashidi, A., Giagka, V., et al. (2023). A Comparative Study of Si3N4 and Al2O3 as Dielectric Materials for Pre-Charged Collapse-Mode CMUTs. In IEEE International Ultrasonics Symposium, IUS. IEEE Computer Society [10.1109/IUS51837.2023.10307389].
A Comparative Study of Si3N4 and Al2O3 as Dielectric Materials for Pre-Charged Collapse-Mode CMUTs
Savoia A. S.;
2023-01-01
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 Si3N4 and Al2O3 when used as a charge storage layer. By measuring the shift in the C-V curve, Si3N4 exhibits a larger shift than Al2O3, indicating a better charge-trapping capability. When using the pre-charged CMUTs as power receivers, the Si3N4 version harvested up to 80 mW -only a few mW more than the Al2O3 - with an efficiency of about 50 %. Accelerated Lifetime Tests predict a lifetime of about 7.8 and 1.2 years for Si3N4 and Al2O3 respectively.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
