Development of piezoelectric micromachined ultrasonic transducers

Piezoelectric micromachined ultrasonic transducers (pMUTs) are an example of the application of MEMS technology to ultrasound generation and detection, which is expected to offer many advantages over conventional transducers. In this work, we investigate pMUTs through novel design and fabrication methods. A finite element (FE) model, with original tools to measure device performance, was developed to design and optimize pMUTs. A pMUT for the operating range of 2-10 MHz in water and having maximized energy coupling coefficient was modeled, designed, fabricated, and tested for its resonance frequency and coupling coefficient. The model predictions for the resonance frequency were in excellent agreement with the measured values, but not as good for the coupling coefficient due to the variability in the measured coupling coefficient. Compared to conventional ultrasonic transducers, pMUTs exhibit superior bandwidth, in excess of 100%, and offer considerable design flexibility, which allows their operation frequency and acoustic impedance to be tailored for numerous applications. (C) 2003 Elsevier B.V. All rights reserved.