Improving PMUT Receive Sensitivity via DC Bias and Piezoelectric Composition

Christopher Cheng; Travis Peters; Ajay Dangi; Sumit Agrawal; Haoyang Chen; Sri-Rajasekhar Kothapalli; Susan Trolier-McKinstry

doi:10.3390/s22155614

Improving PMUT Receive Sensitivity via DC Bias and Piezoelectric Composition

Sensors (Basel). 2022 Jul 27;22(15):5614. doi: 10.3390/s22155614.

Authors

Christopher Cheng¹, Travis Peters¹, Ajay Dangi², Sumit Agrawal², Haoyang Chen², Sri-Rajasekhar Kothapalli², Susan Trolier-McKinstry³

Affiliations

¹ Department of Materials Science and Engineering, Penn State University, University Park, PA 16802, USA.
² Department of Biomedical Engineering, Penn State University, University Park, PA 16802, USA.
³ Department of Materials Science and Engineering and Materials Research Institute, Penn State University, University Park, PA 16802, USA.

Abstract

The receive sensitivity of lead zirconate titanate (PZT) piezoelectric micromachined ultrasound transducers (PMUTs) was improved by applying a DC bias during operation. The PMUT receive sensitivity is governed by the voltage piezoelectric coefficient, h_31,f. With applied DC biases (up to 15 V) on a 2 μm PbZr_0.52Ti_0.48O₃ film, e_31,f increased 1.6 times, permittivity decreased by a factor of 0.6, and the voltage coefficient increased by ~2.5 times. For released PMUT devices, the ultrasound receive sensitivity improved by 2.5 times and the photoacoustic signal improved 1.9 times with 15 V applied DC bias. B-mode photoacoustic imaging experiments showed that with DC bias, the PMUT received clearer photoacoustic signals from pencil leads at 4.3 cm, compared to 3.7 cm without DC bias.

Keywords: DC bias; PMUT; photoacoustics; receive sensitivity.

MeSH terms

Bias
Diagnostic Imaging*
Equipment Design
Transducers*
Ultrasonography / methods

Grants and funding

NSF (DMR-1420620)/National Science Foundation Material Research Science and Engineering Center (MRSEC) sup-ported by the National Science Foundation under grant DMR-1420620 and the National Defense Science and Engineering Graduate Fellowship