High electromechanical coupling piezoelectric micro-machined ultrasonic transducer (PMUT) elements for medical imaging

Abstract

This paper presents a multi-cell lead zirconate titanate (PZT) pMUT element geometrically optimized for high effective electromechanical coupling (k _eff ² ) and acoustic power and manufactured via a commercially viable, array compatible and wafer-scale process. A top-down fabrication approach facilitates achievement of a high fill factor (≈1250 transducers/mm ² ) multi-cell element array, and more substantially, results in a frequency based k _eff ² measurement of 9±1.4% per element, a nearly two fold improvement over the previous state-of-the-art.