title: Piezoelectric micromachined ultrasonic transducers based on PZT thin films.
abstract: This paper describes fabrication and characterization results of piezoelectric micromachined ultrasonic transducers (pMUTs) based on 2-microm-thick Pb(Zr0.53Ti0.47O3) (PZT) thin films. The applied structures are circular plates held at four bridges, thus partially unclamped. A simple analytical model for the fully clamped structure is used as a reference to optimize design parameters such as thickness relations and electrodes, and to provide approximate predictions for coupling coefficients related to previously determined thin film properties. The best coupling coefficient was achieved with a 270-microm plate and amounted to kappa2 = 5.3%. This value compares well with the calculated value based on measured small signal dielectric (epsilon = 1050) and piezoelectric (e3l,f = 15 Cm(-2)) properties of the PZT thin film at 100 kV/cm dc bias. The resonances show relatively large Q-factors, which can be partially explained by the small diameters as compared to the sound wavelength in air and in the test liquid (Fluorinert 77). A transmit-receive experiment with two quasi-identical pMUTs was performed showing significant signal transmission up to a distance of 20 cm in air and 2 cm in the test liquid.
authors.affiliation: Ceramics Laboratory, Swiss Federal Institute of Technology EPFL, CH-1015 Lausanne, Switzerland. paul.muralt@epfl.ch
authors.forename: Paul
authors.initials: P
authors.lastname: Muralt
authors.forename: Nicolas
authors.initials: N
authors.lastname: Ledermann
authors.forename: Jacek
authors.initials: J
authors.lastname: Baborowski
authors.forename: Abdolghaffar
authors.initials: A
authors.lastname: Barzegar
authors.forename: Sandrine
authors.initials: S
authors.lastname: Gentil
authors.forename: Brahim
authors.initials: B
authors.lastname: Belgacem
authors.forename: Sylvain
authors.initials: S
authors.lastname: Petitgrand
authors.forename: Alain
authors.initials: A
authors.lastname: Bosseboeuf
authors.forename: Nava
authors.initials: N
authors.lastname: Setter
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D025802:Electric Capacitance; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004582:Electronics, Medical; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007854:Lead / Q000737:chemistry* / Q000528:radiation effects; D016014:Linear Models; D008567:Membranes, Artificial; D008839:Microelectrodes; D008904:Miniaturization; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods; D015040:Zirconium / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D008567:Membranes, Artificial; C065536:lead titanate zirconate; D007854:Lead; D015040:Zirconium; D014025:Titanium