调幅W(Mo)/Cu纳米多层膜He+离子辐照响应行为

用磁控溅射技术制备不同调幅波长 (L) 的W(Mo)/Cu纳米多层膜,所制膜系在60 keV氦离子 (He⁺) 辐照条件下注入不同剂量: 0, 1×10¹⁷ He⁺/cm², 5×10¹⁷ He⁺/cm². 用X射线衍射仪 (XRD) 和高分辨透射电子显微镜(TEM)表征W(Mo)/Cu纳米多层膜辐照前后微观结构. 研究结果表明: 1) He⁺离子轰击引起温升效应是导致沉积态亚稳相β-W 转变成稳态 α-W相的主因, 而与调幅波长无明确关联; 2) 纳米多层结构中W(Mo) 和Cu膜显现出的辐照耐受性与调幅波长相关, 调幅波长越小, 抗He⁺的辐照性能越强; 3) 在5×10¹⁷ He⁺/cm²注入条件下, 观察到He团簇/泡在纳米结构W(Mo) 和Cu膜中的积聚行为存在明显差异: 在W (Mo) 膜中He团簇/泡的分布与晶粒取向相关, He团簇/泡倾向于沿W (211) 晶面分布; 而Cu膜非晶化且He团簇/泡在其体内呈均匀分布. 关键词： W(Mo)/Cu纳米多层膜 +辐照')" href="#">He⁺辐照 He团簇/泡 相转变     

界面对ZrN/TaN纳米多层膜固氦性能的影响

采用射频磁控溅射方法, 在混合气氛下制备了ZrN/TaN多层膜. 利用X射线衍射、慢正电子束分析、增强质子背散射、扫描电子显微镜, 分别对ZrN/TaN多层膜中相结构、氦相关缺陷、氦含量、截面形貌等进行了分析. 结果表明, 调制周期为30 nm的ZrN/TaN多层膜在600℃退火后, 氦的保持率仍能达到45.6%. 在适当的调制周期下, ZrN/TaN多层膜能够耐氦损伤并且其界面具有一定的固氦性能. 关键词： ZrN/TaN 纳米多层膜 界面 固氦     

界面和择优取向对TiN/ZrN纳米多层膜硬度变化的影响

利用射频反应磁控溅射方法，制备了调制比约为4，调制周期不同的一系列TiN/ZrN纳米多层膜. 利用X射线衍射仪(XRD)、高分辨电子显微镜(HRTEM)和纳米压痕仪(Nanoindentation)对多层膜的调制结构、界面状态和力学性能进行了表征. 研究结果表明TiN/ZrN多层膜具有很好的调制结构，但是在TiN层和ZrN层之间存在一定厚度的界面混合层. 力学性能分析表明：当调制周期小于15 nm时，TiN/ZrN多层膜的硬度介于单一TiN和ZrN薄膜的硬度之间；当调制周期为15.24 nm时，硬度达到最大，但随着调制周期增加，多层膜的硬度基本上保持为常数. 分析了TiN/ZrN多层膜硬度变化的机制，认为界面厚度和择优取向是导致硬度变化的主要原因. 关键词： TiN/ZrN多层膜 界面宽度 择优取向 硬度变化     

一个使用氦基混合气的小单元漂移室的实验研究

利用宇宙线分别研究了一个小单元漂移室在He/C3H8(60/40)和He/CH4(60/40)两种氦基混合气下的性能.作为比较还测试了在Ar/CO2/CH4(89/10/1)混合气下的性能.研究表明上述氦基混合气的空间分辨和dE/dx分辨好于Ar/CO2/CH4(89/10/1)混合气.使用He/C8H8(60/40)可以获得110μm的空间分辨,在30—40次取样下dE/dx分辨可以达到6%—7%.     

反应磁控溅射ZrN/AlON纳米多层膜的晶体生长和超硬效应

采用Zr靶和Al₂O₃靶通过在Ar，N₂混合气氛中进行反应磁控溅射的方法制备了不同AlON调制层厚和不同ZrN调制层厚的两个系列的ZrN/AlON纳米多层膜.利用X射线能量色散谱仪、X射线衍射仪、高分辨透射电子显微镜和微力学探针研究了多层膜的成分、微结构和力学性能.结果表明，在Ar，N₂混合气氛中对Al₂O₃进行溅射的过程中，N原子会部分取代Al₂O₃中的氧原子，形成AlON化合物.在ZrN/AlON纳米多层膜中，由于受到ZrN晶体调制层的模板作用，溅射条件下以非晶态存在的AlON层在其厚度小于0.9nm时被强制晶化并与ZrN层形成共格外延生长；相应地，多层膜的硬度明显提高，最高硬度达到33.0GPa.进一步增加多层膜中AlON调制层的厚度，AlON层形成非晶结构，破坏了多层膜的共格外延生长，导致其硬度逐步降低. 关键词： ZrN/AlON纳米多层膜 外延生长 非晶晶化 力学性能     

含氢氦锆膜的中子反射及弹性反冲探测表征

采用直流磁控溅射方法制备含氢氦的锆膜,利用中子反射和弹性反冲探测两种方法分别对样品中的氢、氦分布以及浓度进行表征,并探究了不同温度退火处理后H、He的变化.实验结果表明:中子反射与弹性反冲探测两种方法的表征结果具有很好的一致性,H、He在锆层中近似均匀分布,氦浓度与溅射的He/Ar比成正比. 300℃退火处理1 h后,样品中的H从Zr层向外迁移和释放,且这种现象随退火温度升高到500℃时更加明显.     

AlN在AlN/VN纳米多层膜中的相转变及其对薄膜力学性能的影响

采用反应磁控溅射制备了AlN/VN纳米多层膜.研究了多层膜调制周期对AlN生长结构的影响以 及纳米多层膜的力学性能.结果表明：小周期多层膜中的AlN以亚稳的立方相(c-AlN)存在并 与VN形成共格外延生长的超晶格.薄膜产生硬度和弹性模量升高的超硬效应.大调制周期下， AlN从立方结构转变为稳定的六方相（h-AlN），并使多层膜形成纳米晶的“砖墙”型结构. 讨论认为VN的模板作用有利于c-AlN的生长，但不能显著提高其临界厚度. 关键词： 薄膜的力学性能 外延生长 亚稳相     

TaN/TiN和NbN/TiN纳米结构多层膜超硬效应及超硬机理研究

采用射频磁控溅射方法制备单层TaN,NbN和TiN薄膜和不同调制周期的TaN/TiN和NbN/TiN纳米多层膜.薄膜采用X射线衍射仪、高分辨率透射电子显微镜和显微硬度仪进行表征.结果表明TaN/TiN和NbN/TiN纳米多层膜在一定的调制周期范围内均呈共格界面,相应地均出现了超硬效应,且最大硬度值接近.分析了TaN/TiN与NbN/TiN纳米多层膜的超硬机理,TaN/TiN的晶格错配度与NbN/TiN的接近,但TaN/TiN的弹性模量差与NbN/TiN的有一定的差别,表明由于晶格错配使共格外延生长在界面处 关键词： TaN/TiN纳米多层膜 NbN/TiN纳米多层膜 外延生长 超硬效应     

界面结构对Cu/Ni多层膜纳米压痕特性影响的分子动力学模拟

金属多层膜调制周期下降到纳米级时,其力学性质会发生显著改变. Cu-Ni晶格失配度约为2.7%,可以形成共格界面和半共格界面,实验中实现沿[111]方向生长的调制周期为几纳米且具有异孪晶界面结构的Cu/Ni多层膜,其力学性质发生显著改变.本文采用分子动力学方法对共格界面、共格孪晶界面、半共格界面、半共格孪晶界面等四种不同界面结构的Cu/Ni多层膜进行纳米压痕模拟,研究压痕过程中不同界面结构类型的形变演化规律以及位错与界面的相互作用,获取Cu/Ni多层膜不同界面结构对其力学性能的影响特征.计算结果表明,不同界面结构的样品在不同压痕深度时表现出的强化或软化作用机理不同,软化机制主要是由于形成了平行于界面的分位错以及孪晶界面的迁移,强化机制主要是由于界面对位错的限定作用以及失配位错网状结构与孪晶界面迁移时所形成的弓形位错之间的相互作用.     

纳米晶LaNiAl薄膜充氦技术研究（英文）

采用离子束辅助磁控溅射方法沉积出了纳米晶LaNiAl膜和纳米晶渗氦LaNiAl膜(膜厚约10μm),通过调节ArHe气氛的比例可控制纳米晶膜中的含氦量(He/LaNiAl的原子分数5.7%~13.8%),通过该方法引入到LaNiAl金属薄膜中的氦量远高于采用球磨法制备的纳米LaNiAl粉中的含氦量。研究结果表明:渗氦LaNiAl膜中的氦含量(原子分数)可达13.9%,氦在膜的深度方向分布均匀;热解析分析恒温条件下沉积的渗氦膜的起始释放温度为848K,最高释放温度为1407K,主释放峰为1080K,初步确定了氦主要是以团簇的形式存在于在纳米晶膜中。     

Diffusion Behavior of Cumulative He Doped in Cu/W Multilayer Nanofilms at Room Temperature

Cu/W multilayer nanofilms are prepared in pure Ar and He/Ar mixing atmosphere by the rf magnetron sputtering method.The cross-sectional morphology and the defect distribution of the Cu/W multilayer nanofilms are characterized by scanning electron microscopy and Doppler broadening positron annihilation spectroscopy.The results show that plenty of point defects can be produced by introducing He during the growth of the multilayer nanoGlms.With the increasing natural storage time,He located in the near surface of the Cu/W multilayer nanofilm at room temperature could be released gradually and induce the segregation of He-related defects due to the diffusion of He and defects.However,more He in the deep region spread along the interface of the Cu/W multilayer nanofilm.Meanwhile,the layer interfaces can still maintain their stability.     

调制结构对c-VC/h-TiB2纳米多层膜的超硬效应的影响

通过磁控溅射法制备了一系列不同调制结构的c-VC/h-TiB2纳米多层膜,采用X射线衍射仪、高分辨透射电子显微镜和纳米力学探针表征了多层膜的微结构和力学性能,研究了纳米多层膜调制结构与超硬效应的关系.基于实验研究结果,建立了立方结构VC和六方结构TiB2组成纳米多层膜时调制结构与硬度的关系图,该图分为四个区域,超硬效应产生于具有明锐界面和共格生长结构的区域中,而在其他区域内调制结构的改变将导致多层膜微结构发生变化,使得硬度相应降低.这一关系图可为类似异结构纳米多层膜获得超硬效应的调制结构设计提供参考.     

Effect of helium/argon gas ratio in a He-Ar-Cu<Superscript>+</Superscript> IR hollow-cathode discharge laser: modeling study and comparison with experiments

The He-Ar-Cu⁺ IR laser operates in a hollow-cathode discharge, typically in a mixture of helium with a few-% Ar. The population inversion of the Cu⁺ ion levels, responsible for laser action, is attributed to asymmetric charge transfer between He⁺ ions and sputtered Cu atoms. The Ar gas is added to promote sputtering of the Cu cathode. In this paper, a hybrid modeling network consisting of several different models for the various plasma species present in a He-Ar-Cu hollow-cathode discharge is applied to investigate the effect of Ar concentration in the gas mixture on the discharge behavior, and to find the optimum He/Ar gas ratio for laser operation. It is found that the densities of electrons, Ar⁺ ions, Ar_m ^* metastable atoms, sputtered Cu atoms and Cu⁺ ions increase upon the addition of more Ar gas, whereas the densities of He⁺ ions, He₂ ⁺ ions and He_m ^* metastable atoms drop considerably. The product of the calculated Cu atom and He⁺ ion densities, which determines the production rate of the upper laser levels, and hence probably also the laser output power, is found to reach a maximum around 1–5 % Ar addition. This calculation result is compared to experimental measurements, and reasonable agreement has been reached. Received: 14 October 2002 / Revised version: 28 November 2002 / Published online: 19 March 2003 RID="*" ID="*"Corresponding author. Fax: +32-3/820-23-76, E-mail: annemie.bogaerts@ua.ac.be     

Determination of the element distribution in films deposited using the plasma focus facility by Rutherford backscattering

The C, Cu and W element profiles in films deposited using a plasma focus facility are studied by the Rutherford backscattering of 2-MeV He⁺ ions. The films are deposited onto glass substrates in Ar plasmaforming gas. The element profiles are found to depend significantly on the kinetic energy of particles. The penetration depth of particles with the velocity ~10⁵ m/s is about 1.5 μm. The corresponding element profiles showing the distribution of elements over the thickness of the glass are non-linear. For each element, the maximum layer depth is observed under the glass surface. The formation of Cu, W and C layers under the glass surface and their overlapping is a feature of films deposited using the plasma focus facility. Such an arrangement of layers evidences the significant difference between this method of film deposition and conventional techniques at low rates of atom deposition, as well as diffusion-based methods. The obtained films are found to have dielectric properties.     

Influence of working gas pressure on the performance of W/Si multilayers

The effect of Ar pressure on the performance of W/Si multilayers is investigated. W/Si multilayers were deposited by a high vacuum DC magnetron sputtering system. The Ar pressure was changed from 1.0 to 5.0 mTorr with an interval of 1.0 mTorr during the deposition process. Electron probe microanalysis and Rutherford backscattering are performed to determine the Ar content incorporated within these multilayers. The results demonstrate that less Ar is incorporated within the sample when more Ar is used in the plasma, which could be explained by the increase of the collision probability and the decrease in the kinetic energy of Ar ions arriving at the substrate when more Ar exists. The grazing incident X-ray reflectivity (GIXR) at 0.154 nm is used to determine the structural parameters of the layers. The results show that the structures of these multilayers prepared at different Ar pressure are very similar and that the interface roughness increases quickly when the Ar pressure is higher than 3.0 mTorr. The measurements of the extreme ultraviolet (EUV) reflectivity indicate that the reflectivity decreases when Ar pressure increases. The fitting results of GIXR and EUV reflectivity curves indicate that with an increase of Ar pressure, the density and decrement of the refractive index are increased for W and decreased for Si, which is mainly due to (1) the decrease in Ar content incorporated within these multilayers which affects their performance and (2) the increase of collision probability for sputtered W and Si, the decrease of their average kinetic energy arriving at the substrate, and thus the loosing of their layers.     

Distribution of Excited Atoms and Ions in a Plasma Generated at the Surface of Ferroelectric Ceramic

The distribution of excited atoms and ions in a plasma generated at the surface of ferroelectric ceramic has been studied. For all studied spectral lines of He I, Ar I, Ar II and hydrogen a decrease of the total line intensity with the increasing distance from the ceramic surface has been found. The shapes of these distributions are characteristic of the specific spectral lines. The distributions for He I lines depend strong on the concentration of argon in the helium — argon mixture. The effect of overpopulation of some excited Ar II ion levels in an argon discharge observed already in a previous work has been found also in the case of a helium — argon plasma.     

Study of Thermal Desorption of Helium from Hydrogenated Zirconium

A new method prepared for helium and hydrogen co-containing Zr films is presented to simulate aging metal tritides, in which direct current magnetron sputtering with a He/H/Ar mixture is used. The retained amount and depth profiles of helium and hydrogen are determined by elastic recoil detection analysis. Thermal desorption spectrometry is applied to investigate He thermal release and the effect of hydrogen. It is found that the hightemperature peaks with a large mount of helium release obviously shifted toward lower temperature at high hydrogen concentration, especially at the hydride transformation region, and that the shapes of the release peaks also changed due to the additional hydrogen. However, at the low-temperature releasing region the peak intense decreases when phase transformation takes place. The mechanism of helium thermal release and the effect of hydrogen are also discussed.     

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介绍了目前解决W/Cu连接界面缓解热应力的方法——添加适配层。在对不同适配层进行分析后,选出最佳W/Cu适配层,再对W/Cu适配层进行结构优化分析,得出选用W/Cu功能梯度材料作为适配层具有足够的结合强度,而且良好的导热性能能有效地缓解热应力。此外,重点阐述了目前成功的制备的W/Cu功能梯度材料用作W/Cu第一壁材料的适配层的常用方法。最后,对W/Cu功能梯度材料用作适配层解决W/Cu第一壁材料连接界面的问题做出了总结和展望。