The microstructural and stress evolution in sputter deposited Ni thin films
The microstructural and stress evolution in sputter deposited Ni thin films
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DOI：
10.1016/j.surfcoat.2021.126973
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发表时间：
2021-02
影响因子：
5.4
通讯作者：
T. Koenig;Z. Rao;E. Chason;G. Tucker;G. Thompson
中科院分区：
文献类型：
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作者：
T. Koenig;Z. Rao;E. Chason;G. Tucker;G. Thompson
我们报道了在速率（0.076和0.250 nm/s）、压力（0.27、0.67和1.33 Pa）和衬底温度（环境、100和200°C）范围内溅射沉积的一系列Ni薄膜的应力和微观结构演变。总的来说，随着溅射压力的增加，无论沉积速率如何，以晶圆曲率测量的应力-厚度乘积都随着压力的增加而变得拉伸并呈趋势。然而，在最低溅射速率和最高衬底温度下，薄膜表现出压缩生长应力。然后，将这些集体数据拟合到一个动力学模型中，该模型解释了晶粒边界、晶粒生长和薄膜内缺陷产生的应力。除了在最低沉积压力下沉积的薄膜外，模型预测的拟合参数与实验测量结果吻合良好。这些特殊的薄膜表现出双峰的晶粒尺寸分布，这不能被模型使用的单一晶粒直径所容纳。尽管如此，在单模态晶粒尺寸下，结果确实为动力学模型提供了支持，有助于确定内部应力发展的各种影响因素，以及它们在薄膜和涂层的桑顿带状形貌描述子背景下的微观结构关系。
We report the stress and microstructural evolution for a series of Ni thin films sputter deposited over a range of rates (0.076 and 0.250 nm/s), pressures (0.27, 0.67 and 1.33 Pa), and substrate temperatures (ambient, 100, and 200 °C). In general, as the sputtering pressure increased, the stress-thickness product, measured by wafer curvature, became tensile and trended with an increase in pressure regardless of the deposition rate. However, at the lowest sputtering rate and highest substrate temperature, the films exhibited a compressive growth stress. The collective data was then fitted to a kinetic model that accounts for the stress generation at the grain boundaries, from grain growth, and from the creation of defects within the film. The model's predicted fitted parameters matched well to the experimental measurements except for films deposited at the lowest deposition pressure. These particular films exhibited a bimodal grain size distribution which could not be accommodated by the model's use of a singular grain diameter. Nevertheless, in monomodal grain sizes, the results do provide support for the kinetic model in helping to ascertain the various contributing factors for the intrinsic stress development and their microstructural relationship in context to the Thornton zonal morphology descriptors for thin films and coatings.