高动态位移ScAlN基超声换能器的设计及制作

Design and Fabrication of ScAlN-Based Ultrasonic Transducer with High Dynamic Displacement

超声探测作为重要的感知技术,其探测性能一直是学术界研究的热点。针对薄膜超声换能器谐振位移低,导致输出声压较低,从而影响探测性能的问题,该文提出了一种高动态位移的薄膜ScAlN基超声换能器结构,该结构直径为360μm,中心处膜层由4根悬梁支柱固支,通过微机电系统(MEMS)微纳加工技术制作了换能器阵列。测试结果表明,该器件谐振频率下,中心处动态位移可达2.16μm/V。此外,该结构使膜层振动模态转变为输出声压更高的活塞型模态,相关工作为空气介质中长距离超声测距传感器的研究奠定了基础。

As an important sensing technology,the performance of the ultrasonic detection has been the focus of academic research.To solve the problem that the low resonant displacement of the thin film ultrasonic transducer leads to the low output sound pressure,which affects the detection performance,a thin film ScAlN-based ultrasonic transducer with high dynamic displacement is proposed in this paper.The diameter of the structure is 360μm,and the film layer at the center is fixed by four cantilever beams.The transducer array is fabricated by MEMS micro-nano machining technology.The test results show that the dynamic displacement at the center of the transducer can reach about 2.16μm/V at its resonant frequency.In addition,the proposed structure can transform the vibration mode of the film into the Piston mode with higher sound pressure.The related work lays a foundation for the research of the long-distance ultrasonic distance sensor in the air medium.