Piezoelectric micromachined ultrasonic transducers (pMUTs) hold great promise for applications ranging from medical imaging to range finding, yet their widespread adoption is hindered by low transmitting sensitivity. To address this limitation, we introduce a metasurface-integrated pMUT featuring a grooved hub-and-spoke structure, fabricated on an $\mathrm{Si}\mathrm{O}$${}_2$/$\mathrm{Pt}$/PZT/$\mathrm{Pt}$/$\mathrm{Si}\mathrm{O}$${}_2$/$\mathrm{Si}$ multilayer stack. In this design, the $\mathrm{Si}\mathrm{O}$${}_2$ vibration layer is strategically deposited above a patterned lead zirconate titanate (PZT) thin film with the precisely microfabricated geometry, a configuration that simultaneously enhances energy transduction and mitigates stress-induced performance deterioration. Experimental measurements validate the efficacy of the design, showing an increase in the electromechanical coupling coefficient from 0.68% to 2.95%. The device achieves a transmitting sensitivity of 0.71 Pa/V at 10 cm, representing a 2.36-fold improvement over conventional designs. Furthermore, the integrated stress-relieving grooves ensure exceptional wafer-scale uniformity, confining resonant frequency deviations to within 4% across an 8-in. wafer. These results, combined with a silicon-based CMOS-compatible fabrication process that emphasizes simplicity and cost-effectiveness, establish the proposed meta-pMUT as a highly viable and competitive technology for the commercialization of next-generation ultrasonic systems.

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• Acoustic metamaterials
• Ultrasonics
• Device fabrication
• Metasurfaces
• Micromechanical devices
• Piezoelectrics
• Transducers
• Ultrasound techniques