A 200-nm-gap Titanium Nitride Composite CMOS-MEMS CMUT for Biomedical Ultrasounds

Hsu, Tzu-Hsuan; Chen, Chao‐Yu; Liu, Chun-You; Li, Ming-Huang; Li, Shenz-Shian

doi:10.1109/fcs.2018.8597500

Cited by 7 publications

(2 citation statements)

References 6 publications

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“…He et al [24] covered the CMUT-membrane with a 5 µm thick parylene-C layer to meet the waterproofing requirements of underwater measurements. Hsu et al [25] used parylene-C to form a 2 µm thick protective layer on the CMUTmembrane and pointed out the key problems. The time for the parylene-C coating to ensure electrical insulation in an aqueous solution was 14 days, and it exhibited poor long-term stability.…”

Section: Introductionmentioning

confidence: 99%

Research on Broadband Matching Method for Capacitive Micromachined Ultrasonic Transducers Based on PDMS/TiO2 Particles

Gao

Zhang

et al. 2022

Micromachines

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The study of impedance matching between a transducer and its working medium is an important part of acoustic transducer design. The traditional quarter wavelength matching (Q-matching) scheme is not suitable for broadband capacitive micromachined ultrasonic transducers. To mitigate this issue, a 0–3 composite broadband matching layer based on polydimethylsiloxane (PDMS) substrate/TiO2 particles is designed to achieve electrical insulation and efficient acoustic energy transfer of underwater capacitive micromachined ultrasonic transducer (CMUT) devices. In this work, the coherent potential approximation model is used to analyze the properties of 0–3 composite materials. Samples are prepared for performance testing to determine the proportion of TiO2 particles that enable the 0–3 composite materials to have the same longitudinal acoustic impedance as water. The CMUT device is packaged by a spin coating and pouring process, and its performance tests are carried out. The experimental results show that the central frequency of the transducer remains at 1.74 MHz, the −6 dB fractional bandwidth increases from 97.3% to 100.3%, the 3 dB directional main beam width increases from 8.3°to 10.3°, the side lobes decrease significantly, and the device has good reception sensitivity. These values imply that the 0–3 composite material has good matching performance, and this matching scheme has the advantages of high efficiency and wide bandwidth. This broadband matching method endows CMUTs with great advantages in underwater detection systems, and it facilitates underwater ultrasonic imaging of CMUT.

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Section: Introductionmentioning

confidence: 99%

Research on Broadband Matching Method for Capacitive Micromachined Ultrasonic Transducers Based on PDMS/TiO2 Particles

Gao

Zhang

et al. 2022

Micromachines

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show abstract

“…Both materials are biocompatible. Parylene-C was used by Zhuang et al [ 10 ] and Hsu et al [ 11 ] in the form of a 2 µm thick protective layer on the CMUT-membrane. Zhuang et al [ 10 ] state the period for which the Parylene-C coating ensured electrical insulation in an aqueous solution as 14 days.…”

Section: Introductionmentioning

confidence: 99%

Encapsulation of Capacitive Micromachined Ultrasonic Transducers (CMUTs) for the Acoustic Communication between Medical Implants

Oevermann

Weber

Tretbar

2021

Sensors

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The aim of this work was to extend conventional medical implants by the possibility of communication between them. For reasons of data security and transmitting distances, this communication should be realized using ultrasound, which is generated and detected by capacitive micromachined ultrasonic transducers (CMUTs). These offer the advantage of an inherent high bandwidth and a high integration capability. To protect the surrounding tissue, it has to be encapsulated. In contrast to previous results of other research groups dealing with the encapsulation of CMUTs, the goal here is to integrate the CMUT into the housing of a medical implant. In this work, CMUTs were designed and fabricated for a center frequency of 2 MHz in water and experimentally tested on their characteristics for operation behind layers of Polyether ether ketone (PEEK) and titanium, two typical materials for the housings of medical implants. It could be shown that with silicone as a coupling layer it is possible to operate a CMUT behind the housing of an implant. Although it changes the characteristics of the CMUT, the setup is found to be well suited for communication between two transducers over a distance of at least 8 cm.

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A Sub-mW/Pixel Zero-Bias CMUT-in-CMOS Receiver Front-End with TiN Electrode

Hsu

Zope

et al. 2020

2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferr

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A 200-nm-gap Titanium Nitride Composite CMOS-MEMS CMUT for Biomedical Ultrasounds

Cited by 7 publications

References 6 publications

Research on Broadband Matching Method for Capacitive Micromachined Ultrasonic Transducers Based on PDMS/TiO2 Particles

Research on Broadband Matching Method for Capacitive Micromachined Ultrasonic Transducers Based on PDMS/TiO2 Particles

Encapsulation of Capacitive Micromachined Ultrasonic Transducers (CMUTs) for the Acoustic Communication between Medical Implants

A Sub-mW/Pixel Zero-Bias CMUT-in-CMOS Receiver Front-End with TiN Electrode

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