Improving wideband performance for ScAlN based piezoelectric MEMS speaker by multi-mode excitation

IF 4.9 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Sensors and Actuators A-physical Pub Date : 2025-06-18 DOI:10.1016/j.sna.2025.116812

Peng Chen , Yan Wang , Junning Zhang , Zihan Li , Hongbin Yu

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引用次数: 0

Abstract

Traditional piezoelectric MEMS speakers that work based on exciting the first-order mode resonance of its electro-acoustic transduction structure have to face challenge in achieving broadband high sound pressure level (SPL) output performance. To address this critical issue, a novel structure design strategy by selectively exciting additional high-order resonance with net air volume pushing characteristic in the transduction structure is presented. Under the effect of resonance amplification, the broadband SPL output capability of the speaker can be effectively enhanced without compromising the compact device size. In proof-of-concept experiment, a Scandium-doped Aluminum Nitride (ScAlN) based piezoelectric MEMS speaker consisting of four identical triangular cantilever beam-like piezoelectric actuators that are arranged into a square configuration is used. Through elaborately designing the cantilever beam structure and the top electrode partition as well as corresponding driving strategy, both of its first-order (4.05 kHz) and the third-order (17.83 kHz) resonance modes can be specifically activated to cover relatively wide frequency range. From the SPL spectrum measurement results using the IEC ear simulator, it can be seen that the as-fabricated speaker prototype can successfully generate SPL higher than 90 dB over the whole audio frequency range. Especially for frequency above 65 Hz, even higher SPL of 100 dB can be achieved, under driving voltage of 20 V_pp despite of its compact active area of 3.2 × 3.2 mm². Moreover, excellent operation linearity has also been revealed even the driving voltage is increased to as high as 30 V_pp and the total harmonic distortion (THD) as low as 0.52 % at 1 kHz (108 dB SPL) can be obtained. Given the competitive wideband performance, the proposed strategy demonstrates potential application perspective in developing piezoelectric MEMS speaker to meet commercial requirements.

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利用多模激励提高基于ScAlN的压电MEMS扬声器的宽带性能

传统的压电式MEMS扬声器基于激发其电声转导结构的一阶模态共振，在实现宽带高声压级（SPL）输出性能方面面临着挑战。为了解决这一关键问题，提出了一种新的结构设计策略，即在转导结构中选择性地激发具有净风量推动特性的附加高阶共振。在共振放大的作用下，扬声器的宽带声压级输出能力可以在不影响器件紧凑尺寸的情况下得到有效增强。在概念验证实验中，使用了一种基于掺钪氮化铝（ScAlN）的压电MEMS扬声器，该扬声器由四个相同的三角形悬臂梁状压电驱动器组成，这些驱动器排列成正方形结构。通过精心设计悬臂梁结构和顶部电极分区以及相应的驱动策略，可以特异性激活其一阶（4.05 kHz）和三阶（17.83 kHz）谐振模式，覆盖较宽的频率范围。从使用IEC耳模拟器的声压级频谱测量结果可以看出，在整个音频范围内，制造的扬声器原型可以成功地产生高于90 dB的声压级。特别是在频率高于65 Hz时，在驱动电压为20 Vpp的情况下，尽管其紧凑的有源面积为3.2 × 3.2 mm²，但仍可以实现100 dB的更高声压级。此外，即使将驱动电压提高到30 Vpp，也能获得良好的工作线性度，并且在1 kHz（108 dB SPL）时总谐波失真（THD）低至0.52 %。鉴于具有竞争力的宽带性能，该策略在开发满足商业需求的压电式MEMS扬声器方面具有潜在的应用前景。

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来源期刊

Sensors and Actuators A-physical 工程技术-工程：电子与电气

CiteScore

8.10

自引率

6.50%

发文量

630

审稿时长

49 days

期刊介绍： Sensors and Actuators A: Physical brings together multidisciplinary interests in one journal entirely devoted to disseminating information on all aspects of research and development of solid-state devices for transducing physical signals. Sensors and Actuators A: Physical regularly publishes original papers, letters to the Editors and from time to time invited review articles within the following device areas: • Fundamentals and Physics, such as: classification of effects, physical effects, measurement theory, modelling of sensors, measurement standards, measurement errors, units and constants, time and frequency measurement. Modeling papers should bring new modeling techniques to the field and be supported by experimental results. • Materials and their Processing, such as: piezoelectric materials, polymers, metal oxides, III-V and II-VI semiconductors, thick and thin films, optical glass fibres, amorphous, polycrystalline and monocrystalline silicon. • Optoelectronic sensors, such as: photovoltaic diodes, photoconductors, photodiodes, phototransistors, positron-sensitive photodetectors, optoisolators, photodiode arrays, charge-coupled devices, light-emitting diodes, injection lasers and liquid-crystal displays. • Mechanical sensors, such as: metallic, thin-film and semiconductor strain gauges, diffused silicon pressure sensors, silicon accelerometers, solid-state displacement transducers, piezo junction devices, piezoelectric field-effect transducers (PiFETs), tunnel-diode strain sensors, surface acoustic wave devices, silicon micromechanical switches, solid-state flow meters and electronic flow controllers. Etc...