Capacitive micromachined ultrasonic transducers (cMUTs) have been attracting attentions as an alternative to traditional piezoelectric transducers for medical diagnostic imaging. A cMUT is composed of a suspended membrane with top electrode and a substrate which acts as a bottom electrode. In operation, the membrane deflects toward the substrate due to electrostatic force by a bias voltage applied between these electrodes. In order to achieve higher sensitivity and low driving voltage, a novel membrane structure partly reinforced by beams to realize uniform deflection at the center part was proposed. It was confirmed that cMUT with the proposed membrane structure has 3 times higher sensitivity than a conventional cMUT. The validity of the proposed cMUT will be verified through the prototyping and evaluation.
M. Sato, Y. Hirai, K. Sugano, T. Tsuchiya, O. Tabata, “Capacitive micromachined ultrasonic transducers with novel membrane design,” The 23rd Conference EUROSENSORS 2009, Lausanne, Switzerland, Sept. 6-9, 2009, pp. 389-392.