【作者】 喻莉；

【导师】 刘祖黎；

【作者基本信息】 华中科技大学 ， 材料物理与化学， 2006， 硕士

【摘要】 薄膜材料不仅包含丰富的物理信息和物理理论基础,还在材料科学、电子技术、信息技术、生物技术等众多领域有着广泛的应用,是近年来迅速发展的研究方向之一。随着计算机技术的进步和对物质不同层次的结构及动态过程的理解的深入,利用计算机对原子尺度的薄膜生长过程进行模拟,是进行薄膜材料研究的有效方法。因为一方面计算机模拟可以得到实验中无法观察到的某些过程,另一方面,计算机模拟可以很方便地改变薄膜生长过程中的各种参数如沉积温度、沉积速率、沉积粒子的入射角、沉积粒子的入射能量等,计算机还可用于研究实验上难以实现的高沉积速率、高沉积温度等极端生长条件下薄膜的生长情况。在本文中,我们用一个三维的动力学蒙特卡罗模型模拟了载能原子沉积薄膜的过程。在普通气相沉积薄膜的模型的基础上,我们还考虑了沉积原子流的入射能量和入射角度对薄膜形貌的影响。其中,由原子的入射能量引起的原子的反射,偏扩散以及局部瞬时热扩散过程,在我们的模型中都进行了考虑。我们模拟了在不同入射能量与入射角度的情况下,外延沉积Cu到Cu(001)基片上时,薄膜的形貌和表面粗糙度的情况。模拟结果表明,能量原子能促使薄膜的表面更加光滑。而且能量的影响在较低的基片温度或是较高的沉积速率时更加显著。而对于某一固定的入射能量,存在一个转变角,在转变角的情况下,沉积的薄膜的表面粗糙度最小。此外,我们还模拟了溅射沉积时的薄膜形貌图,其中粒子的入射能量分布采用实验的近似结果,角度分布采用余弦分布。模拟的结果与实验结果基本吻合。更多还原

【Abstract】 Recently, the study of thin films is one of the most investigated fields due to its unique characteristics and potential wide range of applications in modern science and technology. As the advances of computer technology and of the insight into the structures and dynamic processes of materials at its different levels, the modeling simulation of the growth of thin films on atomic scale is an effective way to study in this field. By simulation of thin films growth, some microscopic processes can be revealed in extreme condition, such as high temperature and high deposition rate.In this paper, A three-dimensional (3D) energy-dependent Kinetic Monte Carlo (KMC) technique is developed to simulate the thin film growth with energetic atoms deposition. We incorporate the effects of the incident kinetic energy and the incident angle of atomic fluxes into the conventional vapor phase deposition model. The atom reflection, the biased diffusion and the athermal diffusion caused by the incident energy and the incident angle are included in our study. We simulate the film morphology and the surface roughness of homoepitaxial Cu films on a Cu(001) substrate with various incident energies and incident angles. The simulation results show that the energetic atoms can enhance the smoothness of the surface. This effect is very significant at low substrate temperature or high deposition rate. For a fixed incident energy, there exists a transition angle, where the surface roughness is the minimum. In addition, the surface morphology of Cu film in sputtering deposition is also studied and the approximate energy and angle distributions of the sputtered atoms are used. The results are in agreement with the experimental results.更多还原