Cargando…

10 MHz Thin-Film PZT-Based Flexible PMUT Array: Finite Element Design and Characterization

Piezoelectric micromachined ultrasound transducers (PMUT) incorporating lead zirconate titanate PbZr(0.52)Ti(0.48)O(3) (PZT) thin films were investigated for miniaturized high-frequency ultrasound systems. A recently developed process to remove a PMUT from an underlying silicon (Si) substrate has en...

Descripción completa

Detalles Bibliográficos
Autores principales: Kim, Jeong Nyeon, Liu, Tianning, Jackson, Thomas N., Choi, Kyusun, Trolier-McKinstry, Susan, Tutwiler, Richard L., Todd, Judith A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7435793/
https://www.ncbi.nlm.nih.gov/pubmed/32759665
http://dx.doi.org/10.3390/s20154335
Descripción
Sumario:Piezoelectric micromachined ultrasound transducers (PMUT) incorporating lead zirconate titanate PbZr(0.52)Ti(0.48)O(3) (PZT) thin films were investigated for miniaturized high-frequency ultrasound systems. A recently developed process to remove a PMUT from an underlying silicon (Si) substrate has enabled curved arrays to be readily formed. This research aimed to improve the design of flexible PMUT arrays using PZFlex, a finite element method software package. A 10 MHz PMUT 2D array working in 3-1 mode was designed. A circular unit-cell was structured from the top, with concentric layers of platinum (Pt)/PZT/Pt/titanium (Ti) on a polyimide (PI) substrate. Pulse-echo and spectral response analyses predicted a center frequency of 10 MHz and bandwidth of 87% under water load and air backing. A 2D array, consisting of the 256 (16 × 16) unit-cells, was created and characterized in terms of pulse-echo and spectral responses, surface displacement profiles, crosstalk, and beam profiles. The 2D array showed: decreased bandwidth due to protracted oscillation decay and guided wave effects; mechanical focal length at 2.9 mm; 3.7 mm depth of field for -6 dB; and -55.6 dB crosstalk. Finite element-based virtual prototyping identified figures of merit—center frequency, bandwidth, depth of field, and crosstalk—that could be optimized to design robust, flexible PMUT arrays.