Electromechanical response of micromachined 1-3 piezoelectric composites: Effect of etched piezo-pillar slope

Abstract

Micromachined single-crystal piezoelectric 1-3 composites are known for high electromechanical coupling coefficients, low acoustic impedance, high processing precision and uniformity, which are desired for high-frequency ultrasound transducers. In this article, based on Smith and Auld’s 1-3 composite thickness-mode oscillation model, the effect of etched side wall slope on the electromechanical characteristics of micromachined piezoelectric 1-3 composites was studied. In specific, strain constant, stiffness, dielectric constant, electromechanical coupling coefficient, acoustic impedance, longitudinal velocity, and frequency of micromachined 1-3 composites were deduced using the developed model. The analytical model was then verified by a COMSOL simulation and experimental measurements of a micromachined composite sample with pitch of 15.9 µm, thickness of 42.8 µm, and etched pillar slope angle of 83.8°. The measured center frequency was 49.05 MHz, electromechanical coupling coefficient was 0.66, dielectric constant was 1178, and strain constant was 26.90 C/m², which all agreed well with the analytical calculations. These results will be helpful in design and fabrication of high-frequency micromachined ultrasound transducers.

Keywords

Electromechanical response 1-3 piezoelectric composite etching slope micro-electromechanical systems

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References

Benjamin

(2001) Recent advances in 1-3 piezoelectric polymer composite transducer technology for AUV/UUV acoustic imaging applications. In: MTS/IEEE conference and exhibition OCEANS, Honolulu, HI, 5–8 November, pp. 26–33. New York: IEEE.

Lee

Zhang

Geng

. (2012) Electroacoustic response of 1-3 piezocomposite transducers for high power applications. Applied Physics Letters 101: 253504.

Jiang

Zhang

Jiang

. (2003) Characterization of piezoelectric materials with large piezoelectric and electromechanical coupling coefficients. Ultrasonics 41: 55–63.

Jiang

Yuan

Cheng

. (2006) Microfabrication of piezoelectric composite ultrasound transducers (PC-MUT). In: IEEE Ultrasonics Symposium, Vancouver,BC, Canada, 3-6 October, pp. 918-921. New York: IEEE.

Jiang

Snook

Cheng

. (2008) Micromachined PMN-PT single crystal composite transducers—15–75 MHz PC-MUT. In: 2008 IEEE ultrasonics symposium, Beijing, China, 2–5 November, pp. 164–167. New York: IEEE.

Kwok

Chan

HLW

Choy

. (1997) Evaluation of the material parameters of piezoelectric materials by various methods. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 44: 733–742.

Safari

Akdoğan

(2008) Piezoelectric and Acoustic Materials for Transducer Applications. New York: Springer.

Satyanarayana

Srinivas

Prasad

. (2012) Design and analysis of MEMS based composite piezoelectric ultrasonic transducer. Electrical and Electronic Engineering 2: 362–373.

Smith

(1990) The application of 1-3 piezocomposites in acoustic transducers. In: IEEE 7th international symposium on applications of ferroelectrics, Urbana-Champaign, IL, 6–8 June, pp. 145–152. New York: IEEE.

10.

Smith

Auld

(1991) Modeling 1-3 composite piezoelectrics: thickness-mode oscillations. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 38: 40–47.

11.

Sottos

Scott

. (1993) Micromechanical behavior of 1-3 piezocomposites. In: Proceedings of SPIE 1916, smart structures and materials 1993: smart materials, Albuquerque, NM, 1 February, pp. 87–96. Bellingham, WA: SPIE.

12.

Standards Committee of the IEEE Ultrasonics (1988) IEEE Standard on Piezoelectricity. ANSI/IEEE Std 176–1987: 0–1. Available at: http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=2511

13.

Sun

Wang

. (2010) High frequency PMN-PT 1-3 composite transducer for ultrasonic imaging application. Ferroelectrics 408: 120–128.

14.

Wang

Ritter

Cao

. (2001) High frequency properties of passive materials for ultrasonic transducers. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 48: 78–84.

15.

Yuan

Jiang

Snook

. (2006) 5I-1 Microfabrication of piezoelectric composite ultrasound transducers (PC-MUT). In: IEEE ultrasonics symposium, Vancouver, BC, Canada, 2–6 October, pp. 922–925. New York: IEEE.

16.

Zhang

Jiang

. (2002) Elastic, dielectric and piezoelectric coefficients of domain engineered 0.70 Pb (MgNb) O-0.30 PbTiO single crystal. AIP conference proceedings 626: 188–197.