PMN-PT single crystal thick films on silicon substrate for high-frequency micromachined ultrasonic transducers

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2010, Vol.98 (1), p.233-237
• Main Authors: Peng, J., Lau, S. T., Chao, C., Dai, J. Y., Chan, H. L. W., Luo, H. S., Zhu, B. P., Zhou, Q. F., Shung, K. K.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Condensed Matter Physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Machines; Manufacturing; Materials science; Micromachining; Nanotechnology; Needles; Noise levels; Optical and Electronic Materials; Physics; Physics and Astronomy; Piezoelectricity and electromechanical effects; Processes; Surfaces and Interfaces; Thick films; Thin Films; Thinning; Transducers; Wafers
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-009-5381-1

In this work, a novel high-frequency ultrasonic transducer structure is realized by using PMNPT-on-silicon technology and silicon micromachining. To prepare the single crystalline PMNPT-on-silicon wafers, a hybrid processing method involving wafer bonding, mechanical lapping and wet chemical thinning is successfully developed. In the transducer structure, the active element is fixed within the stainless steel needle housing. The measured center frequency and −6 dB bandwidth of the transducer are 35 MHz and 34%, respectively. Owing to the superior electromechanical coupling coefficient ( k t ) and high piezoelectric constant ( d 33 ) of PMNPT film, the transducer shows a good energy conversion performance with a very low insertion loss down to 8.3 dB at the center frequency.