Development of Scanning Amplitude-and-Phase Acoustic Measuring Microscope System for Measurement of Distribution of Elastic Moduli

本研究的目的是研制一种用于测量材料表面局部弹性模数分布的扫描幅相测量声显微镜系统。首先，考虑声透镜的特性，将幅相测量声学显微镜应用于复杂V(Z)曲线的数值模拟分析。结果表明，良好的透镜在传递函数上对归一化波数具有较大且稳定的幅度。通过该透镜，在反射函数上清晰地确定了纵横波信号，提高了瑞利波波速的测量精度，并尝试开发软件对扫描工作台进行高效控制。当测量直径为10 mm的局部圆形区域的弹性模量时，测量精度在1 mm^2以下的局部区域小于0.2%。作为重要的工程应用之一，测量了单晶材料和薄膜/衬底结构的力学性能。用扩展到线聚焦声透镜的系统测量了单晶GaAs(001)的各向异性。用玻璃上的金膜作为薄膜/衬底结构的试件。由于薄膜中的纵波和横波太弱，瑞利波和塞泽波的速度是可以估计的。利用表面波色散曲线可以有效地识别薄膜的弹性模数、密度和厚度。

The purpose of the present research is the development of scanning amplitude-and-phase measuring acoustic microscope system to measure distribution of elastic moduli in local area on material surface.At first, the properties of acoustic lenses was considered to apply the amplitude-and-phase measuring acoustic microscope to analysis of complex V(z) curve from numerical simulation. It is obtained that the good lens has large and stable amplitude to normalized wave number on its transfer function. By the lens, the signals of longitudinal and transverse waves are determined on the reflectance function clearly and the precision for wave velocity of Rayleigh's wave is improved.In the system, we tried to develop the software to control the scanning table efficiently. When elastic moduli are measured at local circular area with 10mm diameter, the precision of the measurement is less than 0.2% at local area under 1mm^2. As one of the important applications of engineering, the mechanical properties of single crystal material and thin-film/substrate structures were measured. The anisotropy of single crystal GaAs (001) were determined by the system expanded to line focus acoustic lens. The Gold film on glass were used as the specimen of the film/substrate structure. The velocities of Rayleigh's and Sezawa's waves could be estimated, since the longitudinal and transverse wave are too weak in thin film. Then, the dispersion curve of surface wave is efficient to identify elastic moduli, density and thickness of the film.