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首页> 外文期刊>Journal of Applied Physics >Reducing the grain size of polycrystalline lead films by the use of barriers to grain growth
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Reducing the grain size of polycrystalline lead films by the use of barriers to grain growth

机译：通过使用晶粒生长障碍来减小多晶铅膜的晶粒尺寸

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摘要

The mechanical strength of lead‐alloy films used in Josephson junctions is improved by reducing the grain size. One way to achieve this goal is to reduce the rate of grain growth. The activation energy for barrierless growth during vapor deposition was estimated to be about 540 cal/mole for lead films and is assigned to the ordering of atoms. Because of its small value, instead of reducing the rate of grain growths, it seemed best to stop growth by the application of a barrier layer. This is followed by the nucleation of new grains. Five requirements for a barrier‐to‐grain growth are given out of which the requirement of a high interfacial free energy between barrier and lead is stressed the most. In the experiments Nb, PdSn4, AuIn2, and PdIn3 were used as barriers between lead layers. The grain size of layered films was determined by transmission electron microscopy and was found to be about the same as if the total film thickness were equal to the thickness of one layer. Yet there are small differences between the different barrier layers; their effectiveness increases as their melting points increase. This is because all the requirements for a barrier‐to‐grain growth suggested in this paper are the better fulfilled the higher the melting point. Some of the layered films were tested for hillock formation due to thermal cycles between room temperature and 4.2 K; on some of them, the superconducting transition temperature was measured and nuclear backscattering spectra taken.
机译：通过减小晶粒尺寸，可改善约瑟夫森结中使用的铅合金薄膜的机械强度。实现此目标的一种方法是降低谷物的生长速度。对于铅膜，气相沉积过程中无障碍生长的活化能估计约为540卡/摩尔，并分配给原子顺序。由于其较小的值，因此与其降低晶粒的生长速度，不如通过应用阻挡层来阻止生长，这似乎是最好的。接下来是新晶粒的成核。提出了五种阻碍晶粒生长的要求，其中最强调的是对阻碍物和铅之间的高界面自由能的要求。在实验中，Nb，PdSn4，AuIn2和PdIn3用作铅层之间的势垒。通过透射电子显微镜确定层状膜的晶粒尺寸，发现其与总膜厚等于一层的厚度大致相同。然而，不同的阻挡层之间存在细微的差异。它们的效力随着熔点的增加而增加。这是因为，熔点越高，本文提出的所有阻碍晶粒生长的要求都可以更好地满足。由于在室温至4.2 K之间的热循环，测试了一些层状膜的小丘形成。在其中一些中，测量了超导转变温度并获得了核背散射光谱。

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    《Journal of Applied Physics》 |1983年第2期|P.652-659|共8页
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  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);
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