Inter-relationship of stress and microstructure in BCC and ‘beta’ tungsten films
Inter-relationship of stress and microstructure in BCC and ‘beta’ tungsten films
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BCC 和 β 钨薄膜中应力与微观结构的相互关系
DOI：
10.1016/j.surfcoat.2023.129336
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发表时间：
2023
影响因子：
5.4
通讯作者：
Thompson, Gregory B.
中科院分区：
文献类型：
--
作者：
Johnson, Jonathan A.;Su, Tong;Chason, Eric;Thompson, Gregory B.
在这项工作中，一系列的W膜沉积在不同的沉积速率（0.2，0.5，和1.0 nm/s）和压力（0.27，0.47，0.67，和1.33 Pa）。比较不同沉积速率之间的残余应力，发现在所研究的压力范围内，在较高的沉积速率下，应力变得更加拉伸。在三个最高压力下沉积的薄膜在应力下是拉伸的，具有小晶粒（~15至20 nm），并且稳定通常被称为β-W的亚稳A15相。在最低压力0.27 Pa时，薄膜为压应力薄膜，晶粒尺寸较大（约70 ~ 90 nm），主要稳定体心立方α-W相。如果W晶种层在α-W或β-W生长条件下生长，则随后的W层采用晶种层的相态，与处理条件和/或晶粒尺寸无关，这表明相态最有可能在成核的初始阶段确定。种子层实验还表明，这些层可以促进更厚的β-W膜中的晶粒尺寸更可控，这在以前的工作中没有观察到。应力测量解释在以前开发的动力学模型，包括生长动力学，微观结构的演变，和高能粒子轰击的影响。
In this work, a series of W films are deposited at different deposition rates (0.2, 0.5, and 1.0 nm/s) and pressures (0.27, 0.47, 0.67, and 1.33 Pa). Comparing the residual stresses between different deposition rates, the stress was found to become more tensile at higher depositions rates over the pressure ranges studied. Films deposited at the three highest pressures were tensile in stress, had small grains (~15 to 20 nm), and stabilized the metastable A15 phase often referred to as β-W. At the lowest pressure, 0.27 Pa, the films were compressive in stress, larger grain sizes (~70 to 90 nm), and primarily stabilized the body centered cubic α-W phase. If a W seed layer was grown under either the α-W or β-W growth conditions, the subsequent W layer adopted the phase state of the seed layer, independent of processing conditions and/or grain sizes, suggesting that the phase state is most likely determined in the initial stages of nucleation. The seed layer experiment also suggest that these layers can promote more controlled grain sizes in thicker β-W films, which has not been observed in previous work. The stress measurements are interpreted in terms of a previously developed kinetic model that includes effects of growth kinetics, microstructural evolution, and energetic particle bombardment.