Realization of next generation medical ultrasound systems requires high volume, inexpensive manufacture of efficient and highly sensitive transducers: a need that is currently unmet with the existing bulk piezoceramic technology. As an alternative, piezoelectric micro-machined ultrasonic transducers (pMUTs), leveraging cost effective and array compatible micro-fabrication, have already demonstrated viability for deep penetration imaging via high acoustic pressure output. Although promising, low electromechanical coupling and bandwidth have resulted in many past pMUTs falling short of expectations. This thesis aims to realize pMUT potential starting with the development of an effective single cell model that is further scaled to optimize multi-cell elements in a 1D array. A top-down fabrication approach facilitates achievement of the largest active area of a multi-cell pMUT to date, and more substantially, results in state-of-the-art electromechanical coupling.
Katherine Smyth will receive her Ph.D. in Mechanical Engineering from MIT in 2017 under Professors Sang-Gook Kim and Charles G. Sodini. She received her S.B. and S.M. degrees in mechanical engineering from MIT in 2010 and 2012, respectively. Her current research interests include medical applications, and modeling and fabrication of thin film piezoelectric MEMS and nano-scale devices.