A piezoelectric micromachined ultrasonic transducer with mechanical grooves. (14th July 2021)

• Record Type: Journal Article
• Authors: Zhou, Xuemei; Yi, Yongjie; Cai, Guixiang; Zhang, Jiajia; Huang, He; Liu, Tao; Zhang, Jiahuan; Yu, Hongbing; Mu, Xiaojing
• Is Part Of: Journal of micromechanics and microengineering. Volume 31:Number 8(2021)
• Publication Date: 2021-07-14
• Subjects: AC-PMUT -- mechanical grooves -- transmitting sensitivity -- mechanical coupling coefficient -- quality factor -- AlN; Microelectromechanical systems -- Periodicals; Micromechanics -- Periodicals; 621.38105
• DOI: 10.1088/1361-6439/ac11b1
• Languages: English
• ISSNs: 0960-1317

Abstract

Abstract: This paper presents a novel architecture for annular and circular electrode piezoelectric micromachined ultrasound transducers (AC-PMUTs) with mechanical grooves. The mechanical grooves reduce stress and increase the vibration area of the membrane, resulting in enhanced vibrational deformation amplitude, transmission sensitivity, mechanical coupling coefficient ( k t 2 ), quality factor ( Q ), and emission sound pressure level (SPL). Compared with conventional AC-PMUTs without mechanical grooves, the transmitting displacement sensitivity was measured as 419.4 NM V −1, which increased by 128.73%; the mechanical coupling coefficient ( k t 2 ) was measured as 6.09%, which increased by 116.43%; and the quality factor ( Q ) was measured as 90.68, which is an increase of 241.3%. The mechanical grooves also increased the emission SPL of PMUT at the same operating frequency. In the range of 10 kHz–70 kHz, the emission SPL of the optimum AC-PMUT with mechanical grooves can be improved in the range of 2.8 dB–28.8 dB. In general, AC-PMUTs with mechanical grooves have great potential in various emission ultrasound applications, such as distance measurement and object detection.