单晶硅多晶面表面波波速曲线超声测量方法

Measurement of Surface Acoustic Wave Velocity Curves of Silicon Crystal by Ultrasonic Method

随着晶体材料在航空航天、交通、电子电气工程、能源和环保等领域的广泛应用,对材料特殊性能的研究和检测工作也提出了新的要求。基于声波在材料中传播特性与材料力学性能之间的本构关系,建立单晶硅弹性常数矩阵与表面波波速之间关系的声弹性理论模型,并利用晶面的转换矩阵得到不同晶面下,表面波波速随角度变化的理论曲线。基于线聚焦超声换能器、高精度散焦测量系统和V(f,z)分析法获得单晶硅三个晶面沿不同角度的表面波波速变化曲线,试验测量结果与理论曲线相吻合,表明超声显微镜技术在各向异性材料表面波波速测量方面具有很高的精确度和可靠性。同时,论文还研究了单晶硅的晶体结构与表面波波速之间内在对应关系,为单晶硅等各向异性材料的性能检测与评价奠定了理论与试验基础。

As the crystal materials are applied widely in the fields of aerospace, transportation, electrical and electronic engineering, energy and environmental protection, the new requirements for the researches of their special properties and testing work put forward. Based on the constitutive relationship between the propagation characteristic of acoustic wave in materials and the surface wave velocity, an acoustic elasticity theoretical model of the surface acoustic waves(SAW) velocities of silicon crystal contacting with its elastic constants is established. The theoretical SAW velocities distribution curves of different crystallographic planes versus azimuthal angles are calculated by using the transformation matrix. Experimental measurements of SAW velocities along different azimuthal angles of three crystallographic planes by using the line focusing acoustic transducer, the high-precision defocusing measurement system and V(f, z) analysis, and the experimental curves of SAW velocities are consistent with the theoretical values. It proves that acoustic microscopy(AM) technology is of highly accuracy and reliability for the SAW velocities measurements of anisotropic materials. Meanwhile, the corresponding consistency between the crystal structure and SAW velocities of silicon crystal is studied further, which establishes the theoretical basis for the property detections and evaluations of anisotropic materials including silicon crystal.