Capacitive micromachined ultrasonic transducers (CMUTs) with isolation posts.
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.
Huang
Yongli
Y
Kolo Technologies Inc., San Jose, CA, USA.
Zhuang
Xuefeng
X
Haeggstrom
Edward O
EO
Ergun
A Sanli
AS
Cheng
Ching-Hsiang
CH
Khuri-Yakub
Butrus T
BT
D002138:Calibration; D003198:Computer Simulation; D017076:Computer-Aided Design; D025802:Electric Capacitance; D004582:Electronics, Medical; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008839:Microelectrodes; D008904:Miniaturization; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation*