Pulse-Echo Ultrasound Imaging Using an AlN Piezoelectric Micromachined Ultrasonic Transducer Array With Transmit Beam-Forming

This work demonstrates short-range and high-resolution ultrasonic imaging using 8 MHz aluminum nitride (AlN) piezoelectric micromachined ultrasonic transducer (PMUT) arrays, which are compatible with complementary metal-oxide semiconductor circuitry and wafer-level mass manufacture. Because AlN has a low dielectric constant, the PMUTs have low capacitance and a custom 1.8 V interface application-specified integrated circuit with on-chip charge-pump (1.8 to 32 V) is capable of providing sufficient output current to drive the PMUT array. Transmit beam-forming is used to produce a 90 μm focused acoustic beam-width. A pressure map measured with a needle hydrophone agrees with finite element method-simulations. Finally, 1-D and 2-D pulse-echo imaging was conducted using metal targets.

[1]  D. Blackstock.  Fundamentals of Physical Acoustics , 2000 .

[2]  Bernhard E. Boser,et al.  Broadband piezoelectric micromachined ultrasonic transducers based on dual resonance modes , 2015, 2015 28th IEEE International Conference on Micro Electro Mechanical Systems (MEMS).

[3]  Yipeng Lu,et al.  A High Fill-Factor Annular Array of High Frequency Piezoelectric Micromachined Ultrasonic Transducers , 2015, Journal of Microelectromechanical Systems.

[4]  H. Xie,et al.  Piezeoelectric micromachined ultrasound tranducer array for photoacoustic imaging , 2013, 2013 Transducers & Eurosensors XXVII: The 17th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS & EUROSENSORS XXVII).

[5]  O. Oralkan,et al.  Forward-viewing CMUT arrays for medical imaging , 2004, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[6]  Omer Oralkan,et al.  Capacitive micromachined ultrasonic transducers for medical imaging and therapy , 2011, Journal of micromechanics and microengineering : structures, devices, and systems.

[7]  Yipeng Lu,et al.  High frequency piezoelectric micromachined ultrasonic transducer array for intravascular ultrasound imaging , 2014, 2014 IEEE 27th International Conference on Micro Electro Mechanical Systems (MEMS).

[8]  Xingzhao Liu,et al.  AlN-based piezoelectric micromachined ultrasonic transducer for photoacoustic imaging , 2013 .

[9]  Yipeng Lu,et al.  Modeling, Fabrication, and Characterization of Piezoelectric Micromachined Ultrasonic Transducer Arrays Based on Cavity SOI Wafers , 2015, Journal of Microelectromechanical Systems.

[10]  Abdullah Atalar,et al.  Micromachined two-dimensional array piezoelectrically actuated transducers , 1998 .

[11]  D. T. Yeh,et al.  Experimental characterization of collapse-mode CMUT operation , 2006, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[12]  O. V. von Ramm,et al.  In vivo real-time 3-D intracardiac echo using PMUT arrays , 2014, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control.

[13]  F. Akasheh,et al.  Piezoelectric micromachined ultrasonic transducers: modeling the influence of structural parameters on device performance , 2005, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[14]  Massimo Pappalardo,et al.  Capacitive micromachined ultrasonic transducer (CMUT) arrays for medical imaging , 2006, Microelectron. J..

[15]  Paul Muralt,et al.  Micromachined Ultrasonic Transducers and Acoustic Sensors Based on Piezoelectric Thin Films , 2004 .

[16]  P. Muralt,et al.  PZT thin films for microsensors and actuators: Where do we stand? , 2000, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[17]  Hongsoo Choi,et al.  Fabrication of a two-dimensional piezoelectric micromachined ultrasonic transducer array using a top-crossover-to-bottom structure and metal bridge connections , 2013 .

[18]  A. Barzegar,et al.  Piezoelectric micromachined ultrasonic transducers based on PZT thin films , 2005, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[19]  Bernhard E. Boser,et al.  11.8 Integrated ultrasonic system for measuring body-fat composition , 2015, 2015 IEEE International Solid-State Circuits Conference - (ISSCC) Digest of Technical Papers.

[20]  Byungsub Kim,et al.  An Analog-Digital Hybrid RX Beamformer Chip With Non-Uniform Sampling for Ultrasound Medical Imaging With 2D CMUT Array , 2014, IEEE Transactions on Biomedical Circuits and Systems.

[21]  Makoto Ishida,et al.  Miniature ultrasound acoustic imaging devices using 2-D pMUTs array on epitaxial PZT/SrRuO3/Pt/³-Al2O3/Si structure , 2011, International Solid-State Sensors, Actuators and Microsystems Conference.

[22]  Yipeng Lu,et al.  HIGH FREQUENCY AND HIGH FILL FACTOR PIEZOELECTRIC MICROMACHINED ULTRASONIC TRANSDUCERS BASED ON CAVITY SOI WAFERS , 2014 .

[23]  O. V. von Ramm,et al.  Theory and operation of 2-D array piezoelectric micromachined ultrasound transducers , 2008, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[24]  Bernhard E. Boser,et al.  Ultrasonic fingerprint sensor using a piezoelectric micromachined ultrasonic transducer array integrated with complementary metal oxide semiconductor electronics , 2015 .

[25]  Yongqiang Qiu,et al.  Piezoelectric Micromachined Ultrasound Transducer (PMUT) Arrays for Integrated Sensing, Actuation and Imaging , 2015, Sensors.

[26]  B. Boser,et al.  Short-range and high-resolution ultrasound imaging using an 8 MHz aluminum nitride PMUT array , 2015, 2015 28th IEEE International Conference on Micro Electro Mechanical Systems (MEMS).

[27]  Martin Schoeppler,et al.  Three-dimensional micro electromechanical system piezoelectric ultrasound transducer , 2012 .

[28]  John D. Larson,et al.  Thin film bulk wave acoustic resonators (FBAR) for wireless applications , 2001, 2001 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.01CH37263).

[29]  G.R. Lockwood,et al.  Design and fabrication of annular arrays for high-frequency ultrasound , 2004, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.