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Prof. Ik-Keun Park

Development of GHz-Acoustic Microscopy System for Precision Diagnosis of Hidden Damage in Micro/Nanostructured Thin Films


Prof. Ik-Keun Park

Scanning acoustic microscopy has been well established for decades as a useful tool for nondestructively evaluating the elastic properties of bulk materials. However, a precision diagnostic technique that can be applied to micro/nano-materials is not sufficient to evaluate micro/nanostructured thin films. In addition, hidden damage that affects the mechanical properties of the thin film system is not easy to detect and also leads to failure of any micro/nanostructural components. Therefore, a precision diagnostic technique using GHz-Acoustic Microscopy System(GHz-AMS) with ultra-high resolution was proposed to evaluate micro/nanostructured thin film nondestructively. In this study, several types of nanoscaled thin films were designed and manufactured using nanofabrication techniques for evaluation of hidden damage. The dispersion curves were calculated by the Thomson-Haskell matrix method for layered thin films and compared with the measured leaky surface acoustic wave velocities in several types of specimens with different adhesion properties and thicknesses respectively. According to the results, the GHz-AMS sensor has to be designed and fabricated under optimal conditions. As a preliminary study, 400 MHz and 1 GHz acoustic lenses were designed and fabricated. After the performance of the GHz-AMS sensor is verified, multi-axis control scan algorithm, data acquisition, and signal processing software will be developed as a core component. Finally, a prototype of GHz-AMS will be developed, and the validity will be verified using many types of micro/nanostructure and various materials under a dynamic environment.