Structure and Stress Evolution in Polycrystalline Thin Films

9710139 Thompson这是一项关于在金属薄膜沉积和随后的热加工过程中多晶薄膜的结构和力学状态演变的实验和理论研究。该研究的目标是建立模型和模拟，用于预测晶粒尺寸，晶粒取向和应力演变的过程，作为衬底，薄膜和盖层材料性能的函数，同时考虑沉积条件和随后的热历史。在控制和可变速率加热以及在不同温度下不同时间退火时，使用晶圆曲率测量来监测沉积在衬底上的薄膜中的应力。薄膜材料、盖层、薄膜厚度和薄膜沉积温度是这些实验中变化的参数之一。原位透射电镜观察了在薄膜上加热薄膜的晶粒结构演变，由于热膨胀的差异，薄膜中施加了应变。用x射线分析监测薄膜的质地。通过与实验的比较，随着建模和仿真能力的发展，预测晶粒结构、晶粒取向和应力演化的新的定量能力也得到了发展。这为薄膜的处理提供了技术，这些薄膜的性能针对特定的工程应用进行了优化。多晶薄膜用于电子、微机械和磁性器件。在这些应用中，多晶薄膜的性能和可靠性受到其结构的强烈影响，特别是晶粒尺寸和晶体取向的分布。＊＊＊

9710139 Thompson This is an experimental and theoretical research effort on the evolution of structure and the mechanical state of polycrystalline films during thin metal film deposition and during subsequent thermal processing. The goal of the research is to develop models and simulations which can be used to predict the course of grain size, grain orientation and stress evolution as a function of substrate, film and capping layer material properties, while also considering the deposition conditions and subsequent thermal history. The stresses in films deposited on substrates are monitored using wafer curvature measurements made while heating at controlled and variable rates and while annealing at different temperatures for different times. Film material, capping layers, film thickness, and film deposition temperature are among the varied parameters in these experiments. In situ TEM observations explore grain structure evolution in heated films on thin substrates which impose a strain in the films due to differential thermal expansion. Texture of the films is monitored by X-ray analyses. %%% As modeling and simulation capabilities evolve through comparison with experiments, new quantitative capabilities are developed for predicting grain structure, grain orientation, and stress evolution. This provides techniques for processing of films with properties that are optimized for specific engineering applications. Polycrystalline films are used in electronic, micromechanical, and magnetic devices. In these applications, the performance and reliability of polycrystalline films are strongly affected by their structure, specifically the distribution of grain sizes and crystallographic orientations. ***