共查询到20条相似文献,搜索用时 61 毫秒
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采用直流反应磁控溅射方法在P型(100)Si衬底上制备了Ta-Al—N纳米薄膜与Cu/Ta-Al—N复合膜,并对薄膜样品进行了卤钨灯快速热退火(RTP)。用四探针电阻测试仪(VPP)、AFM、SEM—EDS、Alpha—stepIQ台阶仪和XPd)等分析测试方法对样品的形貌结构与特性进行了分析表征。实验结果表明,本实验条件下制得的Ta-Al—N纳米薄膜表面光滑;随着Al靶溅射功率的增加,Ta-Al—N薄膜中Al含量和方块电阻相应增大,均方根粗糙度降低,而沉积速率变化不大,且Ta-Al—N膜层对Cu扩散的阻挡能力增强。但在过高的温度下退火,导致Cu通过Ta-Al—N的晶界扩散到Ta-Al—N/Si界面并形成Cu3Si,从而引起阻挡层的失效。 相似文献
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Fatigue tests of 2024-T3 aluminum sheet were run to determine the effects of constituent particles and particle clusters on fatigue life for all three metallurgical planes. In addition, a model to account for crack coalescence within particle clusters was developed to determine if particle clusters can be more damaging than single particles as crack nucleation sites. On the LS and ST planes, cracks formed primarily at single particles or holes, indicating that coalescence was not an issue. On the LT plane, coalescence was observed when the particle clusters were aligned with the crack growth direction, and the life was reduced about 30%. The crack coalescence and growth model showed that varying the initial separation between two particles (potential cracks) causes at most about a 15–20% change in fatigue life over a separation range of 5 μm to 1200 μm for a pair of 50 μm2 particles. 相似文献
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Rajesh Katamreddy Ronald Inman Axel Soulet Christos Takoudis 《Thin solid films》2007,515(17):6931-6937
Thin stoichiometric aluminum oxide films were deposited using tris(diethylamino)aluminum precursor and water. Changes in aluminum oxide film and interfacial regions were studied after post deposition annealing under inert ambience at 600, 800 and 1000 °C using Fourier Transform InfraRed (FTIR) spectroscopy, X-ray Photoelectron Spectroscopy, and Scanning Transmission Electron Microscopy (STEM)/Electron Energy Loss spectroscopy (EELS) techniques. STEM/EELS analyses were also done on samples annealed in situ, i.e., inside the electron microscope at temperatures as high as 800 °C. Up to an annealing temperature of 600 °C, the atomic layer deposited alumina film was thermally stable and remained amorphous with no interfacial silica growth observed. After annealing at 800 °C for 5 min, the only change observed was a small increase in the interfacial layer thickness which was found to be mainly silicon oxide without any significant silicate content. Annealing at 1000 °C induced a significant increase in the interfacial layer thickness which consisted of a mixture of silicon oxide and aluminum silicate. The composition of the interfacial layer was found to change with depth, with silicate concentration decreasing with distance from the Si substrate. Also, the FTIR spectra exhibited strong absorption features due to Al-O stretching in condensed AlO6 octahedra which indicate crystallization of the alumina film after annealing at 1000 °C for 5 min. 相似文献
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铜热浸镀铝扩散层生长动力学模型 总被引:2,自引:0,他引:2
采用一浴法对铜进行了热浸镀铝试验,热浸镀时间为10~25s,热浸镀温度为963~1 013K。研究了热浸镀温度和时间对铜铝复合材料界面扩散层厚度的影响,采用XPL-15型偏光显微镜(PM)测量铜铝复合材料扩散层厚度,并依据热浸镀铝试验建立了铜铝复合材料界面扩散层生长动力学模型。结果表明,铜铝复合材料界面扩散层的生长动力学符合抛物线扩散规律,与热浸镀温度的指数成正比,与热浸镀时间成抛物线增长关系;铜热浸镀铝扩散层生长动力学模型的修正系数k与时间t存在线性关系。 相似文献
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研究了液相外延生长的高铝含量的Al_xGa_(1-x)/GaAs结构中的Mg掺杂特性,测量了各种接触扩散时间所对应的载流子浓度分布和表面质量。表明用Mg掺杂和接触扩散,能得到合适的结深和较高的载流子浓度的P-GaAs层。如果母液组份和生长温度恒定,并适当控制接触扩散时间,可以制备出重复性好的均匀高质量P-N结。 相似文献
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The B3LYP-DFT/6-311+G(d) method has been used to optimize the geometries of (AlAs)n neutrals and charged ions in the size range of n = 1–15. Frequency analyses are performed at the B3LYP/6-31G(d) level to check whether the optimized structures are transition states or true minima on the potential energy surfaces of corresponding clusters. The total energies of these clusters are then used to study the evolution of their binding energy, relative stability, and electronic properties as a function of size. The geometries are found to undergo a structural change from two-dimensional to three-dimensional when the cluster contains 6 atoms. The medium size clusters (n = 6–15) display the hollow globular conformers with large surface effect, which may cause the bulk limit still far from my computed results. The geometrical changes are companied by corresponding changes in the nearest-neighbor distances and coordination numbers. For medium size clusters (n = 6–15), both ionization potential and electron affinity have the tendency of decrease when the number of AlAs units in the cluster increases. Some magic clusters in neutral, cationic, and anionic form compared to its neighboring clusters are argued according to the calculated results of the second energy difference and electronic properties. 相似文献
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F. J. Palacios M. P. Iiguez M. J. Lpez J. A. Alonso 《Computational Materials Science》2000,17(2-4):515-519
Molecular dynamics simulations of the impact deposition of metal clusters on fcc metal surfaces are presented. Two-dimensional elongated islands are formed when the incident cluster travels parallel to the surface. For perpendicular incidence the results of the impact event are very sensitive to the relative cohesive properties of the cluster and substrate atoms. 相似文献
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Alan E. Herr Sridhar Canumalla Robert N. Pangborn 《Materials Science and Engineering: A》1995,200(1-2):181-191
Microstructural damage mechanisms owing to thermal cycling and isothermal exposure at elevated temperature are studied for a short alumina-silicate fiber-reinforced aluminum alloy (A356) composite produced by pressure casting. The tensile strength of the metal matrix composite is found to degrade considerably in each case. An X-ray double-crystal diffraction method is employed to study the mechanisms of recovery in the matrix. The fractal dimension of the X-ray “rocking curves” for individual grains in the composite reflects the substructure formation owing to the rearrangement of dislocations into subdomain walls. Recovery by polygonization is more pronounced in the case of thermal cycling than for equivalent isothermal exposure. The residual stresses in the matrix that provide the fiber clamping force undergo more relaxation in the case of isothermal exposure. The two competing damage mechanisms, thermally activated recovery by polygonization and relaxation of clamping stresses in the matrix, result in identical strength degradation (25%) for both thermal cycling and isothermal exposure. 相似文献
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In this paper, we present a study of diffusion and clustering of atoms on the titanium (0001) surface using molecular dynamics
and molecular statics methods. The formation energy of each defect cluster is calculated using a combination of annealing
and quenching techniques. Diffusion mechanisms of clusters are elucidated by the analysis of atomic trajectories, and are
confirmed by calculating energy states along the diffusion path and by fitting the diffusion coefficients to one or more Arrhenius
functions. Our simulations show that the clusters diffuse by a sequence of atomic jumps; once an atom moves forward by half
an atomic diameter, the others follow it. Such a correlated process involves an activation energy that is comparable to that
of an adatom. Atoms in each cluster, especially those in clusters consisting of three and seven atoms, are tightly bound.
However, due to high mobility, the clusters are less likely to be the critical nuclei in three-dimensional growth of thin
films on the (0001) surface. Even the cluster consisting of seven atoms swaps a linear distance of 60 nm during the growth
of one monolayer of thin film under typical deposition conditions and at room temperature, making it ineffective as a critical
nucleus above room temperature.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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研究了铜与硅之间W/Mo-N薄膜的扩散阻挡性能。在Si(100)基片上利用反应溅射沉积一层Mo-N薄膜,然后再利用直流溅射在Mo-N上面沉积Cu/W薄膜。样品在真空下退火,并利用四点探针、X射线衍射分析、扫描电镜分析、俄歇电子能谱原子深度剖析等测试方法研究了Cu/W/Mo-N/Si的热稳定性及W/Mo-N薄膜对铜与硅的扩散阻挡性能。实验分析表明,Cu/W/Mo-N/Si结构具有非常好的热稳定性,在600℃退火30min仍未发生相变,并能有效的阻挡铜与硅之间的扩散。 相似文献
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Hot pressing diffusion bonding of a titanium alloy to a stainless steel with an aluminum alloy interlayer 总被引:1,自引:0,他引:1
The probability and appropriate processing parameters of hot pressing diffusion bonding (HP–DW) of a titanium alloy (TC4) to a stainless steel (1Cr18Ni9Ti) with an aluminum alloy (LF6) interlayer have been investigated. The microstructure of the bonded joints has been observed by optical microscopy, SEM, XRD and EDX, and the main factors affecting hot pressing and diffusion bonding process were analyzed. The results showed that atom diffused well and no intermetallic compound or other brittle compounds appeared at optimum parameters. The fracture way of joints was ductile fracture. With the increment of bonding temperature, large number of intermetallic compounds such as FeAl6, Fe3Al, FeAl2 which were brittle appeared along the interface between the stainless steel and the aluminum alloy interlayer, as a result, the quality of joints was decreased significantly and the fracture way of joints was brittle fracture. 相似文献
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为了分析Gd吸附原子在Cu(001)、Cu(110)和Cu(111)表面的扩散机制,本文用分子动力学对该扩散过程进行模拟。模拟结果表明在Cu(001)和Cu(111)表面,Gd原子通过跳跃机制扩散;在Cu(110)表面,在[110]方向Gd原子通过跳跃机制扩散,而且多步跳跃频率很高,而在[001]方向则通过交换机制扩散。通过对扩散频率的拟合,发现在各种扩散机制都符合Arrhenius公式,从而确定了在Cu(001)和Cu(111)表面扩散势垒分别为0.19eV和0.013eV,在Cu(110)表面,沿[110]方向跳跃扩散势垒和沿[001]方向交换扩散势垒分别为0.097eV和0.33eV。 相似文献
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A. Roy Chowdhuri 《Thin solid films》2004,446(1):155-159
Thin films of aluminum oxide were deposited using trimethylaluminum and oxygen. The deposition rate was found to decrease with increasing temperature. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to investigate the film/substrate interface. When dry O2 was used during deposition, the film/substrate interface was free of any silicon dioxide or aluminum silicate phase. On annealing the as-deposited films in Ar, a layer of silicon dioxide film formed at the interface. XPS results indicated that the O/Al ratio in the as-deposited films was higher than that in stoichiometric Al2O3. However, the ratio was found to decrease in the annealed samples suggesting that excess oxygen present in the deposited films is responsible for the formation of interfacial silicon dioxide layer. Interfacial phase formation was observed in the as-deposited samples, when small amounts of ozone along with oxygen were used as the oxygen precursor. 相似文献
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采用固相合成法制备了La0.8Sr0.2(Ga0.8Mg0.2)0.1Fe0.9O3-δ(LSGMF)混合导体和La0.8Sr0.2Ga0.8Mg0.2O3-δ(LSGM)固体电解质, 利用XRD、TGA、范德堡直流四探针法和热膨胀仪等对试样进行了分析。以LSGMF为致密扩散障碍层, 以LSGM为氧泵层, 采用共压共烧结法制备了极限电流型氧传感器, 利用SEM和EDS对LSGMF/LSGM陶瓷体横截面的微观形貌和成分进行了分析。结果表明: LSGMF具有菱方钙钛矿结构(R-3c空间群), 它在650℃失重速率最快, 其电导率随温度的升高而增大; 300~1000℃范围, LSGM与LSGMF的热膨胀系数分别为12.51×10-6/℃和12.80×10-6/℃。650~850℃范围, 氧传感器具有良好的极限电流平台, lgIL(极限电流IL)与1000/T呈线性关系, LSGMF中氧离子的扩散激活能为0.4008 eV。800℃、0.3mol%<x(O2)<21.0mol%时, 极限电流IL与氧含量x(O2)间的关系为: IL(mA)=10.285x(O2)(mol%), R=0.9982。LSGMF和LSGM结合牢固, 未产生裂纹, EDS分析基本符合各化合物的化学计量比。 相似文献
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The diffusion behaviour in theβ
-Zr(Al) solid solution phase was investigated in the temperature range 1203-1323 K using a thermodynamic approach. The Boltzmann-Matano
relation used for determining interdiffusion coefficients and the Darken’s equations used for evaluating the intrinsic diffusion
coefficients from velocity of movement of markers in diffusion couples were modified suitably. The composition dependent thermodynamic
interdiffusion coefficients were evaluated using chemical potential gradient. Composition and temperature dependence of the
thermodynamic interdiffusion coefficients were also established. The thermodynamic intrinsic diffusion coefficients of Al
and Zr and their temperature dependence were determined using the modified Darken’s equations. 相似文献