Epitaxial Grain Growth in Metallic Thin Films

9408201 Thompson这项研究的目标是定量了解薄膜中颗粒生长过程中织构的起源和演变，以及准确预测作为不同薄膜/基片组合的热和工艺历史函数的颗粒尺寸和取向分布的能力。多晶薄膜中颗粒生长和织构演化的实验和理论研究主要集中在薄膜/衬底界面能最小化和应变能密度最小化的竞争效应。研究内容包括多晶银/单晶镍体系、银/铜，以及在各种不同热膨胀系数的二氧化硅涂层衬底上制备的多晶金属薄膜。应变能通过基材的选择和对热历史的修改来控制。已知的应变是通过四点和三点弯曲施加的。用薄膜X射线衍射法和多种电子衍射法对织构演化进行了表征。使用电子和聚焦离子束显微镜表征晶粒度，并通过测量晶片在加热和晶粒生长过程中和之后的曲率来监测薄膜应力。用于模拟薄膜中颗粒生长的计算机程序将得到改进，以考虑弹性应变和塑性变形薄膜中与取向有关的应变-能量-密度差异。%这项研究将改进用于各种工业应用的薄膜制造技术。***

9408201 Thompson The goal of this study is quantitative understanding of the origins and evolution of texture during grain growth in thin films, and the ability to accurately predict grain size and orientation distributions as a function of thermal and process history of different film/substrate combinations. Experimental and theoretical research on grain growth and texture evolution in polycrystalline films is focused towards the competitive effects on minimization of the film/substrate interface energy and minimization of strain energy densities. The research includes the polycrystalline-silver/single-crystal-nickel system, silver/copper, and a number of polycrystalline metallic films on a variety of silica-coated substrates with different thermal expansion coefficients. Strain energy is controlled through the choice of substrates and through modifications in thermal history. Known strains are imposed using 4-point and 3-point bending. Texture evolution is characterized using thin film X-ray diffraction and several electron diffraction techniques. Grain sizes are characterized using electron and focused ion beam microscopy and film stresses are monitored by measurements of wafer curvature, both during and after heating and grain growth. A computer program for simulation of grain growth in thin films will be improved to account for orientation-dependent strain-energy-density differences, in both elastically strained and plastically deformed films. %%% This research should improve technology for creating thin films used in a variety of industrial applications. ***