Electro-acoustical characterization procedure for cMUTs.

A procedure for the electro-acoustical characterization in air of cMUTs is reported. First, the measured input electrical impedance of the transducer is used to calculate the transducer parameters at different bias voltages by fitting it with the Mason model. Then, the single membrane equivalent circuit can be calculated. Second, the cMUT impulse response is obtained through a send-and-receive experiment to be compared with the one predicted by the Mason model. In order to minimize the influence of the emitter in the obtained impulse response an ad hoc broadband piezoelectric transducer centered at the resonant frequency of the cMUT was fabricated. Using this transducer, no deconvolution of the impulse response of the emitter in the cMUT reception pulse is necessary. The procedure is tested for two cMUTs with silicon-rich nitride as structural layer and different membrane diameters (60 and 70 microm).

[1]  D. Hutchins,et al.  Low-temperature micromachined cMUTs with fully-integrated analogue front-end electronics , 2002, 2002 IEEE Ultrasonics Symposium, 2002. Proceedings..

[2]  Edward Hæggström,et al.  Fabricating capacitive micromachined ultrasonic transducers with wafer-bonding technology , 2003 .

[3]  B. Khuri-Yakub,et al.  Surface micromachined capacitive ultrasonic transducers , 1998, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[4]  A. Albareda,et al.  High sensitive piezoelectric transducers for NDE air borne applications , 2000, 2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121).

[5]  L. Wallman,et al.  Characterisation and comparison of a cMUT versus a piezoelectric transducer for air applications , 2002, 2002 IEEE Ultrasonics Symposium, 2002. Proceedings..

[6]  D. Schindel,et al.  Applications of micromachined capacitance transducers in air-coupled ultrasonics and nondestructive evaluation , 1995, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[7]  D. Greve,et al.  MEMS ultrasonic transducers for the testing of solids , 2003, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[8]  Vittorio Foglietti,et al.  Improvements towards a reliable fabrication process for cMUT , 2003 .

[9]  Characterization of capacitive micromachined ultrasonic transducers in air using optical measurements , 2000, 2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121).

[10]  B. Khuri-Yakub,et al.  Capacitive micromachined ultrasonic transducers: next-generation arrays for acoustic imaging? , 2002, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[11]  Butrus T. Khuri-Yakub,et al.  Fabrication and characterization of surface micromachined capacitive ultrasonic immersion transducers , 1999 .

[12]  Bruce C. S. Chou,et al.  Fabrication of low-stress dielectric thin-film for microsensor applications , 1997, IEEE Electron Device Letters.

[13]  I. Ladabaum,et al.  Curved micromachined ultrasonic transducers , 2003, IEEE Symposium on Ultrasonics, 2003.

[14]  W. P. Mason.  Electromechanical transducers and wave filters , 1942 .

[15]  D A Hutchins,et al.  The characterization of capacitive micromachined ultrasonic transducers in air. , 2002, Ultrasonics.

[16]  F.L. Degertekin,et al.  Simulation and experimental characterization of a 2-D, 3-MHz capacitive micromachined ultrasonic transducer (CMUT) array element , 1999, 1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027).

[17]  Utkan Demirci,et al.  Medical imaging using capacitive micromachined ultrasonic transducer arrays. , 2002, Ultrasonics.

[18]  M. Pappalardo,et al.  One-dimensional capacitative micromachined ultrasonic transducer arrays for echographic probes , 2004 .