Ultrasound Research Today is a free monthly online journal that collates and summarizes the latest research about Ultrasound, including details on screening, diagnosis, pregnancy, detection.

Capacitive micromachined ultrasonic transducers (CMUTs) with isolation posts.

Huang Y, Zhuang X, Haeggstrom EO, Ergun AS, Cheng CH, Khuri-Yakub BT

Kolo Technologies Inc., San Jose, CA, USA.

In this paper, an improved design of a capacitive micromachined ultrasonic transducer (CMUT) is presented. The design improvement aims to address the reliability issues of a CMUT and to extend the device operation beyond the contact (collapse) voltage. The major design novelty is the isolation posts in the vacuum cavities of the CMUT cells instead of full-coverage insulation layers in conventional CMUTs. This eliminates the contact voltage drifting due to charging caused by the insulation layer, and enables repeatable CMUT operation in the post-contact regime. Ultrasonic tests of the CMUTs with isolation posts (PostCMUTs) in air (electrical input impedance and capacitance vs. bias voltage) and immersion (transmission and reception) indicate acoustic performance similar to that obtained from conventional CMUTs while no undesired side effects of this new design is observed.

Published 3 March 2008 in Ultrasonics, 48(1): 74-81.
Full-text of this article is available online (may require subscription).

© 2004-2008 Ultrasound Research Today. All Rights Reserved.