Phase-field models for simulating physical vapor deposition and grain evolution of isotropic single-phase polycrystalline thin films
Phase-field models for simulating physical vapor deposition and grain evolution of isotropic single-phase polycrystalline thin films
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DOI：
10.1016/j.commatsci.2016.06.021
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发表时间：
2016-10-01
影响因子：
3.3
通讯作者：
Spearot, Douglas E.
中科院分区：
文献类型：
--
作者：
Stewart, James A.;Spearot, Douglas E.
提出了基于相场方法的两个模型来模拟物理气相沉积（PVD）过程中的薄膜生长，包括各向同性单相多晶材料的地下微观结构演变。第一个模型将先前的单相材料弹道沉积相场模拟和多晶材料晶粒取向演化相场模拟结合在一起，采用顺序模拟算法。第二个模型将PVD和晶粒演化动力学结合到一个自由能泛函中，用于相场模型。为了说明所提出的模型在捕获复合薄膜生长和亚表面晶粒演变方面的能力，在不同晶粒尺寸的衬底上对一般单相多晶金属进行了PVD模拟。在这两种模型中，当初始衬底晶粒尺寸小于预期的表面特征时，薄膜晶粒通过晶界（GB）迁移变粗，直到晶界与柱状表面特征之间的山谷对齐。因此，每个柱状特征都与不同的地下颗粒相关联，与实验观察结果在定性上一致。当初始基质粒度大于表面柱状特征时，模型之间的差异就会出现。例如，当使用单一自由能泛函方法时，颗粒包含明显的内部低角度变化，这是使用耦合模型无法捕获的。(C) 2016 Elsevier B.V.版权所有
Two models are presented based on the phase-field methodology to simulate thin film growth during physical vapor deposition (PVD), including subsurface microstructure evolution, for isotropic single-phase polycrystalline materials. The first model couples previous phase-field modeling efforts on ballistic deposition of single-phase materials and grain orientation evolution in polycrystalline materials in a sequential simulation algorithm. The second model incorporates both PVD and grain evolution dynamics into a single free energy functional for use in a phase-field model. To illustrate the capability of the proposed models in capturing combined thin film growth and subsurface grain evolution, PVD simulations of a generic single-phase polycrystalline metal are performed on substrates with different grain sizes. In both models, when the initial substrate grain sizes are smaller than the expected surface features, the thin film grains coarsen via grain boundary (GB) migration until the GBs become aligned with the valleys between the columnar surface features. Thus, each columnar feature is associated with a distinct subsurface grain, in qualitative agreement with experimental observations. Differences between the models arise when initial substrate grain sizes are larger than the surface columnar features. For example, when using the single free energy functional approach, grains contain noticeable internal low-angle variations, which are not captured using the coupled model. (C) 2016 Elsevier B.V. All rights reserved.