S&M2217 Research Paper
Published: May 20, 2020
High Fill Factor Array of Piezoelectric Micromachined Ultrasonic Transducers with Large Quality Factor [PDF]
Ding Jiao, Zao Ni, Jiachou Wang, and Xinxin Li
(Received December 21, 2019; Accepted March 18, 2020)
Keywords: PMUT, fill factor, quality factor, acoustic efficiency, aluminum nitride
In this paper, we present a novel piezoelectric micromachined ultrasonic transducer (PMUT) array with a high fill factor and a large quality factor (Q). With the reusable design of etching holes, the pitch between PMUTs is effectively minimized, improving the fill factor of the array. With a newly developed surface micromachining process, the fabricated PMUT array only needs few etching holes to release the structure, and all sealed etching holes are removed from the resonance region, achieving a large Q. The demonstrated process facilitates low-cost volume manufacturing. As a result, a 50 × 50 PMUT array containing 48-μm-diameter PMUTs with a 52 μm pitch achieves a high fill factor of 67%. For an individual PMUT, a large Q of 351 is achieved at a center frequency of 12.62 MHz, the peak displacement is 3.25 nm/V, and the effective electromechanical coupling coefﬁcient is 1.6%. The achieved high fill factor and large Q render the proposed PMUT array promising in applications such as flow sensing, chemical detection, and energy transmission.Corresponding author: Xinxin Li
This work is licensed under a Creative Commons Attribution 4.0 International License.
Cite this article
Ding Jiao, Zao Ni, Jiachou Wang, and Xinxin Li, High Fill Factor Array of Piezoelectric Micromachined Ultrasonic Transducers with Large Quality Factor, Sens. Mater., Vol. 32, No. 5, 2020, p. 1785-1795.