Fe-Ti多层调制膜固态反应扩散的动态原位法X射线衍射研究

本文用动态原位法x 射线衍射研究了Fe-Ti 多层调制膜的固态反应扩散, 比较准确地测量了组份调制衍射峰强度的变化,并同时观测了峰位的移动, 计算出不同温度下Fe-Ti 多层调制膜的扩散系数, 并给出其随时间变化的曲线. 根据扩散系数随时间变化率, 计算出与粘滞弛豫相关的激活能 Q=8.3 士0 .2 kcal/ mol. 关键词：     

热处理Co/C软X射线多层膜的掠入射反射率增强

研究了低温退火Co/C软X射线多层膜中掠入射反射率的增强现象．通过测量一级调制峰强度随退火温度和时间的变化，测得了低至-10^-25m²s^－1的有效扩散系数．由于所研究的Co/C多层膜的调制波长远大于Co-C系统的扩散临界波长，有效扩散系数近似等于真实宏观扩散系数．负的宏观扩散系数表明，在Co-C系统中有相分离的趋势．这一结果可解释为由Miedema宏观原子模型计算得到的正的Co-C系统的混合焓．高退火温度下反射率的降低是界面锐化与界面粗糙化 关键词：     

非晶调制多层膜Nb/Si中的互扩散研究

利用原位Ｘ射线衍射技术得到非晶调制多层膜Ｎｂ／Ｓｉ中的互扩散系数与退火温度的关系，调制周期Ｌ＝３.２ｎｍ的非晶调制多层膜是用粒子溅射方法制备的．温度范围为４２３—５２３Ｋ的有效互扩散系数通过原位测量多层膜的一级调制峰强度与退火温度之间的关系而得到．利用缺陷陷阱延迟扩散机制解释了所得到的扩散系数与退火温度的关系．建立了可以解释较小前置系数的模型 关键词：     

Pd2Si的生成对Pd/Si多层膜衍射性能的影响

本文研究了Pd₂Si的生成对周期性Pd/Si多层膜X射线衍射性能的影响。X射线衍射强度的测量数据表明Pd₂Si的生成对长周期多层膜的衍射强度影响不大,但对短周期多层膜衍射强度的影响较大。在引入折射率修正后,我们不仅用单个峰的位置计算了多层膜的周期,而且还用了以两个峰的位置联立消去折射率修正的方法计算了多层膜的周期,前者的误差大于后者。模拟计算的结果说明:均匀Pd₂Si层的生成不足以解释Pd/Si多层膜衍射强度随退火温度的变化,界面的平整化或粗糙化是影响衍射强度的另一个要素。 关键词：     

Pd_2Si的生成对Pd/Si多层膜衍射性能的影响

本文研究了Pd_2Si的生成对周期性Pd/Si多层膜X射线衍射性能的影响。X射线衍射强度的测量数据表明Pd_2Si的生成对长周期多层膜的衍射强度影响不大,但对短周期多层膜衍射强度的影响较大。在引入折射率修正后,我们不仅用单个峰的位置计算了多层膜的周期,而且还用了以两个峰的位置联立消去折射率修正的方法计算了多层膜的周期,前者的误差大于后者。模拟计算的结果说明:均匀Pd_2Si层的生成不足以解释Pd/Si多层膜衍射强度随退火温度的变化,界面的平整化或粗糙化是影响衍射强度的另一个要素。     

纳米多层膜“软"相结构参量对硬度的Hall-Petch表征

采用直流磁控溅射方法制备了不同调制比的Ni/Al纳米多层膜,利用X射线衍射技术和纳米压入连续刚度法分析了薄膜微结构及塑性变形的尺度依赖性.实验结果表明,尽管调制比有所不同,多层膜的硬度与“软"相的微结构特征参量随调制波长减小具有相似变化规律,说明多层膜的变形机制对“软"相的微结构约束存在敏感性.随着薄膜特征尺度的减小,为统一多层膜中晶界和膜界两种强化机制,提出一个与“软”相相关的表征参量r(r＝L_sub/d,L关键词： 纳米多层膜 塑性变形 调制波长 Hall-Petch关系     

非晶态多层膜和单层膜的低角X射线衍射研究

本文对a-Si:H/(a-SiN_x:H)非晶态周期多层膜和单层膜进行了低角X射线衍射研究。在周期数较少的多层膜衍射的布喇格衍射峰的低角侧发现了一系列次级衍射峰;在单层膜样品的低角衍射中也发现了一系列小峰。对此,我们提出了一个用于计算非晶多层膜和单层膜衍射强度的简单公式,使实验结果得到解释,并提出了一种测量膜厚的方法。 关键词：     

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     

Co/Ti金属磁性多层膜的激光布里渊散射研究(英文)

在室温下利用直流磁控溅射法制备出了具有不同Co层厚度的 [Co(dConm) /Ti(dTinm) ]n 金属磁性多层膜 (其中dCoanddTi是Co和Ti的厚度 ,n薄膜调制周期数 )。在 30 0K下用X射线衍射法 (XRD)和布里渊散射方法研究了Co层厚度分别为dCo=1 ,2 ,2 5 ,3 5nm ,Ti层厚度为dTi=2 5nm的Co/Ti多层膜。XRD的结果所示在Co/Ti多层膜中Co层厚度超过 2 5nm ,其结构类似块材Co的多晶结构。对比之下 ,Co/Ti多层膜中Co层厚度低于 2 5nm ,其XRD衍射峰随Co层厚度减少变的峰形加宽 ,衍射峰的强度减少 ,峰位移动和消失。在Co/Ti多层膜中自旋波的布里渊散射结果表明 :在Co/Ti多层膜中 ,对于dCo>2 5nm磁性呈铁磁性耦合 ,在dCo≤ 2 5nm时 ,其呈反铁磁性耦合。除表面自旋波外 ,在呈反铁磁性耦合的材料中观测到了两个有体特征的自旋波 ,而在呈铁磁耦合的材料中只观测到一个有体特征的自旋波。     

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     

Cu/SiO2/Si(111)体系中Cu和Si的扩散及界面反应

室温下利用磁控溅射在p型Si(111)衬底上沉积了Cu薄膜. 利用X射线衍射和卢瑟福背散射分别对未退火以及在不同温度点退火后样品的结构进行了表征. 在此基础上，研究了Cu/SiO₂/Si(111)体系的扩散和界面反应. 实验结果表明：当退火温度高于450℃时出现明显的扩散现象，并且随着温度的升高，体系扩散现象会更加显著. 当退火温度低于450℃时没有铜硅化合物生成，当温度达到500℃时才有铜硅化合物生成. 关键词： 薄膜 扩散 界面反应 硅化物     

An X-ray diffraction study of the interdiffusion in a KCl:PbCl2 solid solution system

Broadening of X-ray diffraction line profile due to compositional variations can be used as a powerful, non-destructive toll to study the interdiffusion in metallic alloys, binary solid solutions and alloy catalysts. Since powder samples are easy to prepare and have technological importance and KCl, PbCl₂ form solid solution, high purity Aldrich chemicals of KCl and PbCl₂ (-325 mesh, 50 μm) were mixed at a ratio 1:0.1963 by weight. After diffusion anneals at different temperatures, X-ray diffractograms show the shift in KCl and PbCl₂ peaks. The powder becomes amorphous at and above 550°C. Interdiffusion was found to be very fast at the beginning and wask limited to the surface only. The activation energy for such diffusion was found out to be 0.0012 eV. Such a low activation energy has been explained on the basis of surface diffusion mechanism. The degree of interdiffusion (F) as well as diffusion coefficient (D) were also calculated from the concentric sphere model.     

Solid-state amorphization reaction in the system zirconium hydride-cobalt

Crystalline multilayer films of zirconium hydride and cobalt were prepared by a dual ion-beam sputtering technique. The structure of the samples was investigated by X-ray diffraction analysis at low and medium scattering angles and by Rutherford backscattering experiments. During suitable heat treatments a solid-state reaction occurs in ZrH_2+x /Co forming a two-phase amorphous Zr–Co–H alloy. The composition of the amorphous phases reveals similarities to the behaviour of crystalline Zr–Co compounds upon dissolution of hydrogen. At small modulation wavelengths and at temperatures above 300 K an in-situ amorphization reaction occurs during deposition, again leading to a compositionally modulated structure with two amorphous phases.     

XPS study of annealing induced effects on surface and interface electronic properties of Si/Ge nanostructures

The present study is focused on the influence of vacuum thermal treatment on surface/interface electronic properties of Si/Ge multilayer structures (MLS) characterized using X-ray photoelectron spectroscopy (XPS) technique. Desired [Si(5 nm)/Ge(5 nm)]_×10 MLS were prepared using electron beam evaporation technique under ultra high vacuum (UHV) conditions. The core-level XPS spectra of as-deposited as well as multilayer samples annealed at different temperatures such as 100 °C, 150 °C and 200 °C for 1 h show substantial reduction in Ge 2p peak integrated intensity, whereas peak intensity of Si 2p remains almost constant. The complete interdiffusion took place after annealing the sample at 200 °C for 5 h as confirmed from depth profiling of annealed MLS. The asymmetric behaviour in intensity patterns of Si and Ge with annealing was attributed to faster interdiffusion of Si into Ge layer. However, another set of experiments on these MLS annealed at 500 °C suggests that interdiffusion can also be studied by annealing the system at higher temperature for relatively shorter time duration.     

Optimized growth and dielectric properties of barium titanate thin films on polycrystalline Ni foils

Barium titanate(BTO) thin films were deposited on polycrystalline Ni foils by using the polymer assisted deposition(PAD) technique.The growth conditions including ambient and annealing temperatures were carefully optimized based on thermal dynamic analysis to control the oxidation processing and interdiffusion.Crystal structures,surface morphologies,and dielectric performance were examined and compared for BTO thin films annealed under different temperatures.Correlations between the fabrication conditions,microstructures,and dielectric properties were discussed.BTO thin films fabricated under the optimized conditions show good crystalline structure and promising dielectric properties with εr～ 400 and tan δ < 0.025 at 100 kHz.The data demonstrate that BTO films grown on polycrystalline Ni substrates by PAD are promising in device applications.     

Ion scattering studies of strained Si/Si1−xGex superlattices

Helium ion channeling and backscattering experiments have been performed on MBE-grown Si/Si_1−xGe_x superlattices to investigate interdiffusion, defect densities and tetragonal lattice distortion. Rapid Thermal Annealing (RTA) of these structures leads to substantial interdiffusion and strain relaxation. In some cases also relaxation by dislocation formation is observed after RTA, depending on the alloy composition x. Grazing incidence Rutherford backscattering spectroscopy was employed to observe the modulation of the backscattering yield of the superlattices. The modulation decreases due to interdiffusion after RTA. Interdiffusion coefficients were deduced for Ge concentrations between x=0.20 and x=0.70 in the temperature range between 900°C and 1125°C. The diffusivity increases with larger Ge concentrations. The activation energy for interdiffusion is 3.8 ± 0.2 eV.     

Formation of gold nanoparticles in heat-treated reactive co-sputtered Au-SiO2 thin films

In this work, formation of gold nanoparticles in radio frequency (RF) reactive magnetron co-sputtered Au-SiO₂ thin films post annealed at different temperatures in Ar + H₂ atmosphere has been investigated. Optical, surface topography, chemical state and crystalline properties of the prepared films were analyzed by using UV-visible spectrophotometry, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and X-ray diffractometry (XRD) techniques, respectively. Optical absorption spectrum of the Au-SiO₂ thin films annealed at 800 °C showed one surface plasmon resonance (SPR) absorption peak located at 520 nm relating to gold nanoparticles. According to XPS analysis, it was found that the gold nanoparticles had a tendency to accumulate on surface of the heat-treated films in the metallic state. AFM images showed that the nanoparticles were uniformly distributed on the film surface with grain size of about 30 nm. Using XRD analysis average crystalline size of the Au particles was estimated to about 20 nm.     

Influence of annealing temperature on the photoluminescence property of ZnO thin film covered by TiO2 nanoparticles

In this work, ZnO thin films covered by TiO₂ nanoparticles (labeled as TiO₂-ZnO thin films) were prepared by electron beam evaporation. The influence of annealing temperature on the photoluminescence property of the samples was studied. The structures and surface morphologies of the samples were analyzed by X-ray diffraction (XRD) and atomic force microscope, respectively. The photoluminescence was used to investigate the fluorescent properties of the samples. The measurement results show that the ultraviolet emission of ZnO thin films is largely enhanced after they are covered by TiO₂ nanoparticles, while the green emission is suppressed. However, when the annealing temperature is relatively high (≥500 °C), the intensity of ultraviolet emission drops off and a violet emission peak along with a blue emission peak appears. This is probably connected with the atomic interdiffusion between TiO₂ nanoparticles and ZnO thin film. Therefore, selecting a suitable annealing temperature is a key factor for obtaining the most efficient ultraviolet emission from TiO₂-ZnO thin films.