摘要
声表面波技术可无损测量纳米多孔介电薄膜材料的机械特性参数.采用横观各向同性模型表征二维周期性多孔薄膜的结构特性,推导了表面波在周期性纳米多孔薄膜/硅基底结构中的传播模型.通过编程计算数值算例,得到了薄膜各向异性结构特性及弹性模量对表面波色散曲线的影响.结果表明,纳米通孔方向与传播方向间的角度差会对色散曲线产生明显影响,在垂直于通孔的传播方向不能测出弹性模量E′.最后给出了有助于改善测量精度的措施.此模型可用于纳米多孔低介电常数材料各向异性特性测试实验.
Surface acoustic wave （SAW） technique can determine the mechanical properties of nano-porous low dielectric constant （low-k） films nondestructively. The anisotropic structure characters of two-dimensional periodic porous materials were considered in the transversely isotropic model. The theoretical formulas of SAW propagating in the periodic nano-poreus low-k film/silicon substrate layered structure were deduced in detail. Through computing numerical examples, the effects of anisotrepic structure characters and elastic modulus of the films on the SAW dispersive curves were found. The result shows that the dispersive curves are greatly affected by the angle between the SAW propagation directions and the nano-pores directions. Elastic modulus E＇ cannot be measured along the propagation direction which is perpendicular to the nano-pores direction. On the basis of these effects, methods for improving the measurement accuracy were provided. The model can be used for the anisotrepic characters test of nano-porous low-k materials.
出处
《天津大学学报》
EI
CAS
CSCD
北大核心
2007年第12期1391-1396,共6页
Journal of Tianjin University(Science and Technology)
基金
国家自然科学基金资助项目(60406003)
教育部留学回国人员科研启动基金资助项目
