Innovations in piezoelectric materials for ultrasound transducers

Thomas R. Shrout

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Scopus citations

Abstract

Piezoelectric materials lie at the heart of ultrasonic transducers. For transducers used in medical imaging (3-7 MHz), PZT-5H ceramics offer high electromechanical coupling (k33 ≥ 75%), resulting in good bandwidth and sensitivity. As transducer arrays become smaller with increasing frequency, the development of high permittivity (εRT > 7,000 vs. 3,400 for PZT-5H), piezoelectrics based on polycrystalline PMN-PT, provide improved electrical impedance matching. Advanced medical diagnostic techniques, including contrast and harmonic imaging, have taken advantage of the recent development in single crystal Relaxor-PTs that offer coupling k33's > 90% and subsequently, significant increases in bandwidth. For small animal, ophthalmology and cellular imaging, higher resolution is demanded, thus requiring transducers operational in the range of 20-100 MHz. Advancements in ceramic processing include pore-free and fine-grain (≤1 micron) piezoelectric ceramics of PT and PZT, being an "enabling" technology, allowing the fabrication of high frequency single element and annular arrays. Innovations in the fabrication of high frequency arrays (≥ 30 MHz) include tape casting and sol-gel molding techniques. Of particular significance, DRIE (deep reaction ion etching), has demonstrated the ability to mill out ultrafine features, allowing 1-3 crystal-polymer composites operational at frequencies > 60 MHz, far beyond that achieved by current state-of-the-art dicing.

Original languageEnglish (US)
Title of host publication17th IEEE International Symposium on the Applications of Ferroelectrics, ISAF 2008
DOIs
StatePublished - Dec 1 2008
Event17th IEEE International Symposium on the Applications of Ferroelectrics, ISAF 2008 - Santa Fe, NM, United States
Duration: Feb 23 2008Feb 28 2008

Publication series

NameIEEE International Symposium on Applications of Ferroelectrics
Volume2

Other

Other17th IEEE International Symposium on the Applications of Ferroelectrics, ISAF 2008
CountryUnited States
CitySanta Fe, NM
Period2/23/082/28/08

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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