{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,16]],"date-time":"2026-06-16T07:50:33Z","timestamp":1781596233535,"version":"3.54.5"},"reference-count":87,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2015,4,3]],"date-time":"2015-04-03T00:00:00Z","timestamp":1428019200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Many applications of ultrasound for sensing, actuation and imaging require miniaturized and low power transducers and transducer arrays integrated with electronic systems. Piezoelectric micromachined ultrasound transducers (PMUTs), diaphragm-like thin film flexural transducers typically formed on silicon substrates, are a potential solution for integrated transducer arrays. This paper presents an overview of the current development status of PMUTs and a discussion of their suitability for miniaturized and integrated devices. The thin film piezoelectric materials required to functionalize these devices are discussed, followed by the microfabrication techniques used to create PMUT elements and the constraints the fabrication imposes on device design. Approaches for electrical interconnection and integration with on-chip electronics are discussed. Electrical and acoustic measurements from fabricated PMUT arrays with up to 320 diaphragm elements are presented. The PMUTs are shown to be broadband devices with an operating frequency which is tunable by tailoring the lateral dimensions of the flexural membrane or the thicknesses of the constituent layers. Finally, the outlook for future development of PMUT technology and the potential applications made feasible by integrated PMUT devices are discussed.<\/jats:p>","DOI":"10.3390\/s150408020","type":"journal-article","created":{"date-parts":[[2015,4,7]],"date-time":"2015-04-07T03:47:46Z","timestamp":1428378466000},"page":"8020-8041","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":364,"title":["Piezoelectric Micromachined Ultrasound Transducer (PMUT) Arrays for Integrated Sensing, Actuation and Imaging"],"prefix":"10.3390","volume":"15","author":[{"given":"Yongqiang","family":"Qiu","sequence":"first","affiliation":[{"name":"Institute for Medical Science and Technology, University of Dundee, Dundee DD2 1FD, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James","family":"Gigliotti","sequence":"additional","affiliation":[{"name":"Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA"},{"name":"Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Margeaux","family":"Wallace","sequence":"additional","affiliation":[{"name":"Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Flavio","family":"Griggio","sequence":"additional","affiliation":[{"name":"Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA"},{"name":"Intel Corporation, Hillsboro, OR 97124, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christine","family":"Demore","sequence":"additional","affiliation":[{"name":"Institute for Medical Science and Technology, University of Dundee, Dundee DD2 1FD, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sandy","family":"Cochran","sequence":"additional","affiliation":[{"name":"Institute for Medical Science and Technology, University of Dundee, Dundee DD2 1FD, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Susan","family":"Trolier-McKinstry","sequence":"additional","affiliation":[{"name":"Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2015,4,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"525","DOI":"10.1016\/j.ndteint.2006.03.006","article-title":"Ultrasonic arrays for non-destructive evaluation: A review","volume":"39","author":"Drinkwater","year":"2006","journal-title":"NDT E Int."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"144","DOI":"10.3390\/s140100144","article-title":"High-temperature piezoelectric sensing","volume":"14","author":"Jiang","year":"2013","journal-title":"Sensors"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1016\/j.sna.2009.04.001","article-title":"Piezoelectric ultrasonic micro\/milli-scale actuators","volume":"152","author":"Watson","year":"2009","journal-title":"Sens. Actuators A Phys."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1188","DOI":"10.1016\/S0140-6736(58)91905-6","article-title":"Investigation of abdominal masses by pulsed ultrasound","volume":"271","author":"Donald","year":"1958","journal-title":"Lancet"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1109\/51.544511","article-title":"3-D ultrasound imaging: a review","volume":"15","author":"Fenster","year":"1996","journal-title":"IEEE Eng. Med. Biol. Mag."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1046\/j.1540-8175.2001.00317.x","article-title":"Ter High Intensity Focused Ultrasound for the Treatment of Tumors","volume":"18","author":"Haar","year":"2001","journal-title":"Echocardiography"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"14806","DOI":"10.3390\/s140814806","article-title":"Acoustic devices for particle and cell manipulation and sensing","volume":"14","author":"Qiu","year":"2014","journal-title":"Sensors"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1002\/jctb.280440106","article-title":"Cell manipulation in ultrasonic standing wave fields","volume":"44","author":"Coakley","year":"1989","journal-title":"J. Chem. Technol. Biotechnol."},{"key":"ref_9","unstructured":"Cheeke, J.D.N. (2012). Fundamentals and Applications of Ultrasonic Waves, CRC Press. [2nd ed.]."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Nakamura, K. (2012). Ultrasonic Transducers, Woodhead Publishing Limited.","DOI":"10.1533\/9780857096302"},{"key":"ref_11","unstructured":"176-1987\u2014IEEE Standard on Piezoelectricity. Available online: http:\/\/ieeexplore.ieee.org\/xpl\/articleDetails.jsp?arnumber=26560&contentType=Standards."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1643","DOI":"10.1002\/bit.23073","article-title":"Targeted cell immobilization by ultrasound microbeam","volume":"108","author":"Lee","year":"2011","journal-title":"Biotechnol. Bioeng."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Cobbold, R.S.C. (2006). Foundations of Biomedical Ultrasound, Oxford University Press.","DOI":"10.1093\/oso\/9780195168310.001.0001"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1109\/51.544509","article-title":"Ultrasonic transducers and arrays","volume":"15","author":"Shung","year":"1996","journal-title":"IEEE Eng. Med. Biol. Mag."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1911","DOI":"10.1109\/TUFFC.2014.006480","article-title":"Mass-Spring Matching Layers for High-Frequency Ultrasound Transducers: A New Technique Using Vacuum Deposition","volume":"61","author":"Brown","year":"2014","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"745","DOI":"10.7863\/jum.2006.25.6.745","article-title":"Applications of 2-dimensional matrix array for 3- and 4-dimensional examination of the fetus: A pictorial essay","volume":"25","author":"Espinoza","year":"2006","journal-title":"J. Ultrasound Med."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1177\/016173460903100403","article-title":"New fabrication techniques for ring-array transducers for real-time 3D intravascular ultrasound","volume":"31","author":"Light","year":"2009","journal-title":"Ultrason. Imaging"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1652","DOI":"10.1109\/TUFFC.2002.1159845","article-title":"Optimizing the beam pattern of a forward-viewing ring-annular ultrasound array for intravascular imaging","volume":"49","author":"Wang","year":"2002","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1053\/euje.2001.0128","article-title":"Intracardiac echocardiography","volume":"2","author":"Bruce","year":"2001","journal-title":"Eur. J. Echocardiogr."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"678","DOI":"10.1109\/58.677612","article-title":"Surface micromachined capacitive ultrasonic transducers","volume":"45","author":"Ladabaum","year":"1998","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1109\/TUFFC.2014.6722610","article-title":"Single-chip CMUT-on-CMOS front-end system for real-time volumetric IVUS and ICE imaging","volume":"61","author":"Gurun","year":"2014","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1245","DOI":"10.1109\/TUFFC.2013.2688","article-title":"A comparison between conventional and collapse-mode capacitive micromachined ultrasonic transducers in 10-MHz 1-D arrays","volume":"60","author":"Park","year":"2013","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"3674","DOI":"10.1063\/1.117185","article-title":"Silicon micromachined ultrasonic immersion transducers","volume":"69","author":"Soh","year":"1996","journal-title":"Appl. Phys. Lett."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"774","DOI":"10.1016\/S0041-624X(99)00085-2","article-title":"Micromachined ultrasound transducers with improved coupling factors from a CMOS compatible process","volume":"38","author":"Eccardt","year":"2000","journal-title":"Ultrasonics"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"54004","DOI":"10.1088\/0960-1317\/21\/5\/054004","article-title":"Capacitive micromachined ultrasonic transducers for medical imaging and therapy","volume":"21","author":"Oralkan","year":"2011","journal-title":"J. Micromech. Microeng."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"960","DOI":"10.1109\/58.655620","article-title":"Micromachined high frequency ferroelectric sonar transducers","volume":"44","author":"Bernstein","year":"1997","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1397","DOI":"10.1063\/1.121067","article-title":"Micromachined two-dimensional array piezoelectrically actuated transducers","volume":"72","author":"Atalar","year":"1998","journal-title":"Appl. Phys. Lett."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"302","DOI":"10.1016\/S0924-4247(02)00037-7","article-title":"Arrayed ultrasonic microsensors with high directivity for in-air use using PZT thin film on silicon diaphragms","volume":"97\u201398","author":"Yamashita","year":"2002","journal-title":"Sens. Actuators A Phys."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1023\/B:JECR.0000034004.99355.8b","article-title":"Micromachined ultrasonic transducers and acoustic sensors based on piezoelectric thin films","volume":"12","author":"Muralt","year":"2004","journal-title":"J. Electroceram."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"275","DOI":"10.1016\/j.sna.2003.11.022","article-title":"Development of piezoelectric micromachined ultrasonic transducers","volume":"111","author":"Akasheh","year":"2004","journal-title":"Sens. Actuators A Phys."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"033508","DOI":"10.1063\/1.1855417","article-title":"Ultrasound radiating performances of piezoelectric micromachined ultrasonic transmitter","volume":"86","author":"Wang","year":"2005","journal-title":"Appl. Phys. Lett."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"2276","DOI":"10.1109\/TUFFC.2005.1563270","article-title":"Piezoelectric micromachined ultrasonic transducers based on PZT thin films","volume":"52","author":"Muralt","year":"2005","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"2484","DOI":"10.1109\/TUFFC.956","article-title":"Theory and operation of 2-D array piezoelectric micromachined ultrasound transducers","volume":"55","author":"Dausch","year":"2008","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"253101","DOI":"10.1063\/1.4772469","article-title":"Three-dimensional micro electromechanical system piezoelectric ultrasound transducer","volume":"101","author":"Hajati","year":"2012","journal-title":"Appl. Phys. Lett."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1754","DOI":"10.1109\/TUFFC.2014.006452","article-title":"In vivo real-time 3-D intracardiac echo using PMUT arrays","volume":"61","author":"Dausch","year":"2014","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Griggio, F., Demore, C.E.M., Kim, H., Gigliotti, J., Qiu, Y., Jackson, T.N., Tutwiler, R.L., Cochran, S., and Trolier-McKinstry, S. (2012, January 7\u201310). Micromachined diaphragm transducers for miniaturised ultrasound arrays. Proceedings of 2012 IEEE International Ultrasonics Symposium, Dresden, Germany.","DOI":"10.1109\/ULTSYM.2012.0503"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"521","DOI":"10.1016\/j.sna.2004.10.019","article-title":"Micromachined piezoelectric diaphragms actuated by ring shaped interdigitated transducer electrodes","volume":"119","author":"Hong","year":"2005","journal-title":"Sens. Actuators A Phys."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"697","DOI":"10.1109\/TUFFC.2006.1621496","article-title":"Vibration of micromachined circular piezoelectric diaphragms","volume":"53","author":"Hong","year":"2006","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Bernstein, J.J., Bottari, J., Houston, K., Kirkos, G., Miller, R., Xu, B., Ye, Y., and Cross, L.E. (1999, January 17\u201320). Advanced MEMS ferroelectric ultrasound 2D arrays. Proceedings of 1999 IEEE Ultrasonics Symposium, Caesars Tahoe, NV, USA.","DOI":"10.1109\/ULTSYM.1999.849201"},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Klee, M., Mauczok, R., van Heesch, C., Boots, H., de Wild, M., op het Veld, B., Soer, W., Schmitz, G., and Mleczko, M. (2011, January 18\u201321). Piezoelectric thin film platform for ultrasound transducer arrays. Proceedings of 2011 IEEE International Ultrasonics Symposium, Orlando, FL, USA.","DOI":"10.1109\/ULTSYM.2011.6293445"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"012008","DOI":"10.1088\/1757-899X\/8\/1\/012008","article-title":"Ferroelectric and piezoelectric thin films and their applications for integrated capacitors, piezoelectric ultrasound transducers and piezoelectric switches","volume":"8","author":"Klee","year":"2010","journal-title":"IOP Conf. Ser. Mater. Sci. Eng."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1023\/B:JECR.0000033998.72845.51","article-title":"Thin film piezoelectrics for MEMS","volume":"12","author":"Muralt","year":"2004","journal-title":"J. Electroceram."},{"key":"ref_43","unstructured":"Hong, E. (2004). Surface Micromachined Peristaltic Pumps Using Lead Zirconate Titanate Film. [Ph.D. Thesis, The Pennsylvania State University]."},{"key":"ref_44","unstructured":"Timoshenko, S.P., and Woinowsky-Krieger, S. (1959). Theory of Plates and Shells, McGraw-Hill."},{"key":"ref_45","unstructured":"Morse, P.M., and Ingard, K.U. (1987). Theoretical Acoustics, Princeton University Press."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1023\/B:JECR.0000034000.11787.90","article-title":"Microfabrication of piezoelectric MEMS","volume":"12","author":"Baborowski","year":"2004","journal-title":"J. Electroceram."},{"key":"ref_47","unstructured":"Ergun, A.S., Cheng, C.-H., Oralkan, O., Johnson, J., Jagannathan, H., Demirci, U., Yaralioglu, G.G., Karaman, M., and Khuri-Yakub, B.T. (2002, January 8\u201311). Broadband capacitive micromachined ultrasonic transducers ranging from 10 kHz to 60 MHz for imaging arrays and more. Proceedings of 2002 IEEE Ultrasonics Symposium, Munich, Germany."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1184","DOI":"10.1109\/TUFFC.2003.1235329","article-title":"A new regime for operating capacitive micromachined ultrasonic transducers","volume":"50","author":"Bayram","year":"2003","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"455","DOI":"10.1109\/TUFFC.2005.1417268","article-title":"Piezoelectric micromachined ultrasonic transducers: Modeling the influence of structural parameters on device performance","volume":"52","author":"Akasheh","year":"2005","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_50","unstructured":"Vernet, J.L., Steichen, W., Lardat, R., Garcia, O., and Gelly, J.F. (2001, January 7\u201310). PMUTS design optimization for medical probes applications. Proceedings of 2001 IEEE Ultrasonics Symposium, Atlanta, GA, USA."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1016\/j.pmatsci.2010.09.001","article-title":"Piezoelectric films for high frequency ultrasonic transducers in biomedical applications","volume":"56","author":"Zhou","year":"2011","journal-title":"Prog. Mater. Sci."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"485","DOI":"10.1016\/j.sna.2005.10.054","article-title":"Micromachined thick film piezoelectric ultrasonic transducer array","volume":"130\u2013131","author":"Wang","year":"2006","journal-title":"Sens. Actuators A Phys."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"990","DOI":"10.1109\/TUFFC.2012.2284","article-title":"Theoretical modeling and equivalent electric circuit of a bimorph piezoelectric micromachined ultrasonic transducer","volume":"59","author":"Sammoura","year":"2012","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"573","DOI":"10.1109\/TUFFC.2002.1002456","article-title":"Piezoelectrically actuated flextensional micromachined ultrasound transducers. I. Theory","volume":"49","author":"Percin","year":"2002","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"328","DOI":"10.1016\/j.ultras.2012.06.015","article-title":"Optimizing the electrode size of circular bimorph plates with different boundary conditions for maximum deflection of piezoelectric micromachined ultrasonic transducers","volume":"53","author":"Sammoura","year":"2013","journal-title":"Ultrasonics"},{"key":"ref_56","unstructured":"Jaffe, B., Cook, W.R., and Jaffe, H.L. (1971). Piezoelectric Ceramics, Academic Press."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1109\/16.43810","article-title":"Micromachining for improvement of integrated ultrasonic transducer sensitivity","volume":"37","author":"Mo","year":"1990","journal-title":"IEEE Trans. Electron Devices"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"48","DOI":"10.1109\/58.166810","article-title":"Crosstalk reduction with a micromachined diaphragm structure for integrated ultrasound transducer arrays","volume":"39","author":"Mo","year":"1992","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_59","doi-asserted-by":"crossref","unstructured":"Shelton, S., Chan, M.-L., Park, H., Horsley, D., Boser, B., Izyumin, I., Przybyla, R., Frey, T., Judy, M., and Nunan, K. (23, January 19). CMOS-compatible AlN piezoelectric micromachined ultrasonic transducers. Proceedings of 2009 IEEE International Ultrasonics Symposium, Rome, Italy.","DOI":"10.1109\/ULTSYM.2009.5441602"},{"key":"ref_60","doi-asserted-by":"crossref","unstructured":"Guedes, A., Shelton, S., Przybyla, R., Izyumin, I., Boser, B., and Horsley, D.A. (2011, January 5\u20139). Aluminum nitride pMUT based on a flexurally-suspended membrane. Proceedings of 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference, Beijing, China.","DOI":"10.1109\/TRANSDUCERS.2011.5969223"},{"key":"ref_61","doi-asserted-by":"crossref","unstructured":"Percin, G., and Khuri-Yakub, B. (1997, January 5\u20138). Micromachined 2-D array piezoelectrically actuated flextensional transducers. Proceedings of 1997 IEEE Ultrasonics Symposium Proceedings, Toronto, ON, Canada.","DOI":"10.1117\/12.323916"},{"key":"ref_62","doi-asserted-by":"crossref","unstructured":"Suo, Z., Hao, Z., and Qiao, D. (2012, January 23\u201325). The designing and manufacturing of 1 MHz piezoelectric micro-machined ultrasonic transducer. Proceedings of 2012 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA), Shanghai, China.","DOI":"10.1109\/SPAWDA.2012.6464022"},{"key":"ref_63","unstructured":"Percin, G., and Khuri-Yakub, B.T. (2001, January 7\u201310). Piezoelectrically actuated flextensional MUTs. Proceedings of 2001 IEEE Ultrasonics Symposium, Atlanta, GA, USA."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1016\/S0041-624X(02)00157-9","article-title":"Piezoelectrically actuated flextensional micromachined ultrasound transducers","volume":"40","year":"2002","journal-title":"Ultrasonics"},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"202906","DOI":"10.1063\/1.4831988","article-title":"Monolithic ultrasonic integrated circuits based on micromachined semi-ellipsoidal piezoelectric domes","volume":"103","author":"Hajati","year":"2013","journal-title":"Appl. Phys. Lett."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"903","DOI":"10.1109\/58.852073","article-title":"PZT thin films for microsensors and actuators: Where do we stand?","volume":"47","author":"Muralt","year":"2000","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_67","unstructured":"Akai, D., Yogi, T., Kamja, I., Numata, Y., Ozaki, K., Sawada, K., Okada, N., Higuchi, K., and Ishida, M. (2011, January 5\u20139). Miniature ultrasound acoustic imaging devices using 2-D pMUTs array on epitaxial PZT\/SrRuO3\/Pt\/\u03b3-Al2O3\/Si structure. Proceedings of 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference, Beijing, China."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"2422","DOI":"10.1109\/TUFFC.2007.555","article-title":"High frequency piezoelectric MEMS ultrasound transducers","volume":"54","author":"Mina","year":"2007","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_69","doi-asserted-by":"crossref","unstructured":"Baborowski, J., Ledermann, N., and Muralt, P. (2002, January 8\u201311). Piezoelectric micromachined transducers (PMUT\u2019s) based on PZT thin films. Proceedings of 2002 IEEE Ultrasonics Symposium, Munich, Germany.","DOI":"10.1557\/PROC-741-J12.4"},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"125037","DOI":"10.1088\/0960-1317\/23\/12\/125037","article-title":"Fabrication of a two-dimensional piezoelectric micromachined ultrasonic transducer array using a top-crossover-to-bottom structure and metal bridge connections","volume":"23","author":"Jung","year":"2013","journal-title":"J. Micromech. Microeng."},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"9624","DOI":"10.3390\/s130809624","article-title":"An ultra-high element density pMUT array with low crosstalk for 3-D medical imaging","volume":"13","author":"Yang","year":"2013","journal-title":"Sensors"},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"157604","DOI":"10.1103\/PhysRevLett.108.157604","article-title":"Substrate clamping effects on irreversible domain wall dynamics in lead zirconate titanate thin films","volume":"108","author":"Griggio","year":"2012","journal-title":"Phys. Rev. Lett."},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1080\/10584580390258930","article-title":"Simulation and characterization of piezoelectric micromachined ultrasonic transducers (PMUT\u2019s) based on PZT\/SOI membranes","volume":"54","author":"Baborowski","year":"2010","journal-title":"Integr. Ferroelectr."},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"1715","DOI":"10.1109\/JMEMS.2006.883575","article-title":"The effect of design and process parameters on electromechanical coupling for a thin-film PZT membrane","volume":"15","author":"Cho","year":"2006","journal-title":"J. Microelectromech. Syst."},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1016\/j.sna.2005.11.001","article-title":"Sensitivity improvement of diaphragm type ultrasonic sensors by complementary piezoelectric polarization","volume":"127","author":"Yamashita","year":"2006","journal-title":"Sens. Actuators A Phys."},{"key":"ref_76","doi-asserted-by":"crossref","unstructured":"Dausch, D.E., Gilchrist, K.H., Castellucci, J.B., and Chou, D.R. (2007, January 28\u201331). Performance of flexure-mode pMUT 2D arrays. Proceedings of 2007 IEEE Ultrasonics Symposium, New York, NY, USA.","DOI":"10.1109\/ULTSYM.2007.266"},{"key":"ref_77","doi-asserted-by":"crossref","unstructured":"Dausch, D.E., Gilchrist, K.H., Carlson, J.R., Castellucci, J.B., Chou, D.R., and von Ramm, O.T. (2010, January 28\u201331). Improved pulse-echo imaging performance for flexure-mode pMUT arrays. Proceedings of 2010 IEEE International Ultrasonics Symposium, New York, NY, USA.","DOI":"10.1109\/ULTSYM.2010.5935826"},{"key":"ref_78","doi-asserted-by":"crossref","first-page":"585","DOI":"10.1109\/TUFFC.2002.1002457","article-title":"Piezoelectrically actuated flextensional micromachined ultrasound transducers. II. Fabrication and experiments","volume":"49","author":"Percin","year":"2002","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_79","doi-asserted-by":"crossref","unstructured":"Ren, T., Shu, Y., Yang, Y., Zhou, C.-J., Wang, Y., Tian, H., Zhang, C.-H., Sun, H., and Liu, X. (2012, January 3\u20135). Micromachined piezoelectric devices for acoustic applications. Proceedings of 2012 IEEE International Conference on Electron Devices and Solid State Circuit (EDSSC), Bangkok, Thailand.","DOI":"10.1109\/EDSSC.2012.6482856"},{"key":"ref_80","unstructured":"Fu, D., Ren, T., Chen, H., Yang, Y., Kong, X., Ren, Y., Liao, W., and Liu, L. (2009, January 23\u201327). A novel method for fabricating 2-D array piezoelectric micromachined ultrasonic transducers for medical imaging. Proceedings of 2009 18th IEEE International Symposium on the Applications of Ferroelectrics, Xi\u2019an, China."},{"key":"ref_81","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1016\/j.sna.2003.11.015","article-title":"Ultrasonic micro array sensors using piezoelectric thin films and resonant frequency tuning","volume":"114","author":"Yamashita","year":"2004","journal-title":"Sens. Actuators A Phys."},{"key":"ref_82","doi-asserted-by":"crossref","first-page":"2289","DOI":"10.1109\/TUFFC.2005.1563271","article-title":"Fabrication and characterization of piezoelectric micromachined ultrasonic transducers with thick composite PZT films","volume":"52","author":"Wang","year":"2005","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_83","doi-asserted-by":"crossref","unstructured":"Mendoza-Lopez, J., and Sanchez-Lopez, C. (2013, January 10\u201312). Electromechanical Performance Comparison for Different Piezoelectric Micromachined Ultrasonic Transducer Element Geometries. Proceedings of 2013 UKSim 15th International Conference on Computer Modelling and Simulation, Cambridge, UK.","DOI":"10.1109\/UKSim.2013.40"},{"key":"ref_84","doi-asserted-by":"crossref","unstructured":"Wang, Y.-F., Ren, T.-L., Yang, Y., Chen, H., Zhou, C.-J., Wang, L.-G., and Liu, L.-T. (2011, January 23\u201327). High-density pMUT array for 3-D ultrasonic imaging based on reverse-bonding structure. Proceedings of 2011 IEEE 24th International Conference on Micro Electro Mechanical Systems, Cancun, Mexico.","DOI":"10.1109\/MEMSYS.2011.5734605"},{"key":"ref_85","doi-asserted-by":"crossref","unstructured":"Wang, Y.-F., Yang, Y., Ren, T.-L., Chen, H., Liao, W.-J., Kong, X.-M., Wang, L.-G., Zhou, C.-J., Fu, D., and Liu, L.-T. (2010, January 16\u201318). Ultrasonic transducer array design for medical imaging based on MEMS technologies. Proceedings of 2010 3rd Intersnational Conference on Biomedical Engineering and Informatics, Yantai, China.","DOI":"10.1109\/BMEI.2010.5640053"},{"key":"ref_86","unstructured":"MacLennan, D. (2010). Fundamental Characterisation and Early Functional Testing of Micromoulded Piezocomposites. [Eng.D. Thesis, University of Strathclyde]."},{"key":"ref_87","doi-asserted-by":"crossref","first-page":"1782","DOI":"10.1109\/TUFFC.2011.2015","article-title":"Designing piezoelectric films for micro electromechanical systems","volume":"58","author":"Griggio","year":"2011","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/4\/8020\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T20:44:22Z","timestamp":1760215462000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/4\/8020"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,4,3]]},"references-count":87,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2015,4]]}},"alternative-id":["s150408020"],"URL":"https:\/\/doi.org\/10.3390\/s150408020","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2015,4,3]]}}}