PZT/Si界面氧化反应机理及动力学研究

运用俄歇电子能谱深度剖析和线形分析研究了PZT／Si界面氧化反应的机理和动力学过程。研究结果表明，在PZT／Si样品的热处理过程中，环境气氛中的氧可以透过PZT薄膜层扩散到PZT／Si界面，并与硅基底反应形成SiO2界面层。界面氧化反应由氧在PZT层和SiO2层中的扩散过程所控制。     

Ti/Si(100)体系界面扩散反应动力学研究

采用移动边界条件下扩散问题的处理方法，综合界面反应和扩散两个过程对界面硅化物形成的影响，建立起Ti／Si（100）界面扩散反应动力学理论模型，并拟合快速热退火处理后试样界面Auger深度分析谱，得到Ti，Si在相应界质中扩散系数和表现反应活化能。研究结果表明，Ti／Si体系界面TiSi2生成经历了一个由反应动力学控制到扩散控制的过渡。Si从其晶格中解离并扩散到Ti／TiSi2界面是制约扩散过程的关键因素。     

电子能谱研究生长高质量CeO_2/Si异质结

用低能双离子束淀积技术，在清洁的Si衬底上外延生长出了CeO2／Si异质结构。利用俄歇电子能谱、X射线光电子能谱的深度剖析技术对此类样品进行了测量分析。结果表明，样品界面清晰、陡峭，无氧化硅生成，这反映了外延层与Si衬底间过渡区很窄；外延层内组成元素Ce，O分布均匀，为正化学比CeO2相。原生样品经高温退火后，界面出现了氧化硅层，且过渡层增厚。最后讨论了有关影响CeO2／Si外延生长质量的因素，可认为高质量CeO2／Si结构生长的关键主要依赖于生长初期Si衬底表面不受氧化污染。为此，在IBD生长时，采取了一系列技术措施，得到了满意的结果。     

激光加热条件下 SnPb共晶钎料与Au/Ni/Cu焊盘界面反应动力学

激光重熔在电子封装领域中SnPb共晶钎料凸点制作方面存在极大的优势。采用扫描电子显微镜（SEM）分析了激光加热条件下SnPb共晶钎料与Au/Ni/Cu焊盘之间的界面反应，探讨了钎料中的溶解与扩散动力学。结果表明：CnPb共晶钎料在激光加热瞬间与Au/Ni/Cu焊盘中的Au发生反应，生成Au-Sn金属间化合物，其形貌和分布与激光输入能量密切相关；随着激光输入能量的增加，Au-Su化合物由边境连续层状转变为针状，最后以细小颗粒弥散分布在钎料内部。     

Cu基板表面镀镍浸金保护层对无铅焊点可靠性的影响

结合Sn-3.5Ag和Sn-3.0Ag-0.5Cu两种无铅钎料研究了镀镍浸金层(Electroless Nickel Immersion Gold,ENIG)表面层对焊点界面反应以及力学性能的影响。结果表明,钎焊后在Sn-3.5Ag/ENIG/Cu界面主要生成(Ni_yCu_(1-y))_3Sn_4,在Sn-3.0Ag-0.5Cu/ENIG/Cu界面主要生成(Cu_xNi_(1-x))_6Sn_5。在Sn基钎料/ENIG(Ni)/Cu界面处生成金属间化合物的种类及形貌由焊点中Cu原子含量决定。在时效过程中,ENIG表面层中Ni层有效抑制了焊点界面处金属间化合物的生长,减缓了焊点剪切性能的下降。在钎焊过程中ENIG表面层中的Au层不参与界面反应而是进入钎料基体与Sn反应,但是在时效过程中Au原子向界面迁移并造成焊点界面金属间化合物成分和焊点剪切强度的明显变化。     

PZT/Si薄膜的扩散反应研究

运用XPS和AES研究了PZT薄膜／Si在热处理过程中的薄膜及界面化学反应：在热处理过程中，气氛中的氧气通过PZT的缺陷通道扩散到PZT／Si界面上，并与界面上的硅发生氧化反应形成SiO2界面层。同时基底上的硅通过PZT的缺陷扩散到样品表面形成SiO2表面层。此外，在PZT／Si界面上，Ti的氧化物和Si发生还原反应，形成了TISix金属硅化物，并残留在PZT膜层和SiO2界面层中。在PZT膜层内，有机结碳和钛的氧化物发生还原反应形成了TiCx物种，并存在于PZT膜层中。     

CVD金刚石表面金属化Cr/Cu/Ni/Au的研究

用化学气相沉积（CVD）金刚石表面金属化，制备了多层膜Cr／Cu／Ni／Au，膜层与CVD金刚石基体间的附着强度高。运用X射线衍射（XRD）、扫描电镜（SEM）和差热分析（DTA）对Cr／CVD金刚石界面进行了分析，发现在金属化温度低于300℃时，Cr与CVD金刚石之间无化学反应，并对附着机制进行了探讨。在对Cr／CVD金刚石进行热处理时发现，在474．6～970℃之间，DTA曲线有明显的吸热效应，即界面有化学反应产生。在经900℃左右热处理后，XRD分析界面有Cr3C2和Cr7C3生成。     

Si3N4陶瓷/Nb/Cu/Ni/Inconel 600界面反应层形成机制研究

观察分析了Si3N4陶瓷/Nb/Cu/Ni/Inconel600界面处反应层的形貌、元素分布、反应层中的相结构、界面反应以及反应层的生长规律,研究了Si3N4陶瓷/Nb/Cu/Ni/Inconel600界面处反应层的形成机制.研究结果表明:在连接过程中,Cu层首先熔化,Nb、Ni向液态Cu中扩散溶解形成Cu-Nb-Ni合金,液态合金中的Nb和Ni向Si3N4表面扩散聚集并与Si3N4反应形成反应层;Si3N4侧的反应层主要物相是NbN和Nb、Ni的硅化物,Ni基合金侧反应相主要是NbNi3和Cu-Ni合金;在连接温度为1403 K的条件下,随着连接时间的增加,界面反应层厚度先快速增加,再缓慢增加.     

Ti/SiO_2界面反应的研究

运用俄歇深度剖析和俄歇化学效应研究了Ti／SiO2的界面还原反应。结果表明，在薄膜样品的制备过程中，金属Ti可以和SiO2发生界面还原反应，形成TiSi和TiO2物种。薄膜样品在RTA处理时，Ti和SiO2的界面反应大幅度地增加，尤其是当RTA温度高于700℃时，界面反应增加得更快。700℃温度可能是Ti和SiO2界面反应的活化温度。随着反应时间的增加，界面反应也相应增加。当Ti层的厚度增加时，也有利于Ti和SiO2的界面反应。     

感应加热重熔无铅钎料凸台的界面反应及剪切性能

感应自发热重熔（ISHR）技术在电子互连的应用中具有明显的三维选择性加热和快速加热等优点．该方法能够很好地解决由于无铅钎料的应用引起的日益严重的诸多问题，如球栅阵列中各钎料球受热不均匀和芯片基板与钎料球同时受热等．为此，采用ISHR进行了无铅钎料Sn3．5Ag在Au／Ni／Cu焊盘上的重熔实验、高温老化实验以及凸台剪切实验．由实验结果可知钎料凸台可以提供足够的剪切强度．文中讨论了界面反应和金属间化合物的演化．在老化期间界面处生长了连续的Ni3Sn4金属间化合物层，同时在钎料体内部生成了分散的（Aux，Ni1-x）Sn4化合物．金属间化合物的生长速度与老化时间的平方根成正比。由此可以判断金属间化合物的生长是一种扩散控制过程．     

XPS结合氩离子溅射剖析Si/C多层膜的化学状态

采用X射线光电子能谱结合氩离子溅射对用作锂离子电池负极的Si/C多层膜进行了表面测试及深度剖析,获得了Si/C多层膜结构中不同深度位置的成分及化学状态.分析结果表明,Si/C多层膜中各层Si、C薄膜之间存在界面元素相互扩散,扩散至相邻层薄膜中的Si、C元素主要以化合物SiC形式存在,且处于不同位置的SiC的化学键能受周...     

Graphene growth at the interface between Ni catalyst layer and SiO2/Si substrate

Graphene was synthesized deliberately at the interface between Ni film and SiO2/Si substrate as well as on top surface of Ni film using chemical vapor deposition (CVD) which is suitable for large-scale and low-cost synthesis of graphene. The carbon atom injected at the top surface of Ni film can penetrate and reach to the Ni/SiO2 interface for the formation of graphene. Once we have the graphene in between Ni film and SiO2/Si substrate, the substrate spontaneously provides insulating SiO2 layer and we may easily get graphene/SiO2/Si structure simply by discarding Ni film. This growth of graphene at the interface can exclude graphene transfer step for electronic application. Raman spectroscopy and optical microscopy show that graphene was successfully synthesized at the back of Ni film and the coverage of graphene varies with temperature and time of synthesis. The coverage of graphene at the interface depends on the amount of carbon atoms diffused into the back of Ni film.     

Investigation of interface properties of Ti/Ni/Ag thin films on Si substrate

The interface structure and the adhesion of direct current (DC) sputtered Ti/Ni/Ag thin film metallization on n⁺Si substrate has been investigated. It is shown that beside the chemical preparation of the Si surface prior to sputtering also thermal annealing of sputtered metal structure has strong influence on the adhesion of sputtered layers to the silicon. Energy dispersive X-ray spectroscopy (EDS) analysis were performed on both, the delaminated layers and on the silicon surface to determine the exact delaminating interface, which was found to be between Si and Ti layer. Auger electron spectroscopy (AES) profile revealed no traces of contamination at Ti-Si interface. Measured high tensile residual stress, particularly in sputtered Ni layer (1.4-2 GPa) is found to reduce the metal stack adhesion.     

Characterization of sputter deposited Au/Ni/Al multilayers on Si substrates

Multilayered Au/Ni/Al thin film metallization deposited by DC sputtering on n⁺Si substrates has been investigated. AES depth profiling was performed to reveal the concentration depth profiles of the Au/Ni/Al multilayers before and after annealing at different temperatures in the range 623-723 K. It was found that Ni aluminide layers begin to form during heat treatments at temperatures above 623 K. In addition to this process, Ni was found to diffuse significantly through the Au layer and segregates at the surface, proportionally to the increased annealing temperature. Consequently, the Ni oxidation process was found to take place thus causing the degradation of electrical contact. On the other hand Ni diffuses faster as well toward the Si/Al interface. No contamination traces at interfaces were observed. Electrical measurements of the metallized diode forward characteristics showed minor influence of the metallization heat treatment on the series resistance. Degradations were observed only in the reverse characteristics if the annealing was performed above 723 K.     

渐进因子分析法在Ta2O5／Ta样品俄歇深度剖析研究中的应用

首次利用渐进因子分析法研究了Ｔａ２Ｏ５／Ｔａ样品的俄歇深度剖析过程，获得了样品中Ｔａ的三种不同化学态Ｔａ、Ｔａ２Ｏ５和ＴａＯｘ，并发现Ｔａ２Ｏ５薄膜中经Ａｒ＋离子束轰击后产生的亚稳态产物ＴａＯｘ的ｘ值为１．６，含量接近４０％。Ｔａ２Ｏ５薄膜在深度剖析中未分解出游离态的Ｔａ成分。     

Effect of Applied Pressure on the Joining of Combustion Synthesized Ni3Al Intermetallics with Al Alloy

We focused on the surface reinforcement of ligth weight casting alloys with Ni-AI intermetallic compounds by in-situ combustion reaction to improve the surface properties of non-ferrous casting components.In our previous works,green compact of elemental Ni and Al powders were reacted to form Ni-3Al intermetallic compound by SHS （Self-propagating high temperature synthesis） reaction with the heat of molten Al alloy and simultaneously bonded with Al casting alloy.But some defects such as tiny cracks and porosities were remained in the reacted compact.So we applied pressure to prevent thermal cracks and fill up the pores with liquid Al alloy by squeeze casting process.The compressed Al alloy bonded with the Ni-3Al intermetallic compound was sectioned and observed by optical microscopy and scanning electron microscopy （SEM）.The stoichiometric compositions of the intermetallics formed around the bonded interface and in the reacted compact were identified by energy dispersive spectroscopy （EDS） and electron probe micro analysis （EPMA）. Si rich layer was formed on the Al alloy side near the bonded interface by the sequential solidification of Al alloy.The porosities observed in the reacted Ni-3Al compact were filled up with the liquid AI alloy.The Si particles from the molten Al alloy were detected in the pores of reacted Ni-3Al intermetallic compact.The Al casting alloy and Ni-3Al intermetallic compound were joined very soundly by applying pressure to the liquid Al alloy.     

Hydrogen effect on fracture toughness of thin film/substrate interfaces

The effect of hydrogen on the interface fracture toughness of two nano-film/substrate structures, Ni/Si and Cu/Si, were evaluated using four-point bend specimens with and without hydrogen charging. Hydrogen typically decreases the fracture toughness of materials. However, we found in this study that the interfacial toughness between the Ni film and the Si substrate increased due to the presence of hydrogen, while that of Cu/Si decreased. Nanoindentation experiments for the Ni and Cu films revealed that local plasticity in the Ni and Cu films is promoted by the charged hydrogen. The critical stress intensity at the Ni/Si interface crack considering the plasticity of Ni, namely the true fracture toughness, is scarcely influenced by the existence of hydrogen. The apparent increase in fracture toughness of the Ni/Si interface is due to the large stress relaxation near the crack tip caused by softening due to the presence of hydrogen. Although the promotion of plastic deformation of Cu relaxes the stress intensity at the Cu/Si interface crack, the apparent interfacial toughness still decreases because of the significant decrease in the true toughness due to the presence of hydrogen.     

Ni induced lateral crystallization of high density Ge-dots/Si heterostructures

In this work, we propose a novel method for obtaining high-density Ge-dots/Si multilayered heterostructures. The high-density self-assembled Ge dots are firstly grown on a-Si layer using low-pressure chemical vapor deposition (LPCVD), and then low-temperature recrystallized by Ni based metal induced lateral crystallization (MILC). According to optical micrograph, microprobe Raman spectroscopy and transmission electron microscopy (TEM) observations, it has been found that the Ni induced lateral crystallized Si film has large leaf-like grains elongated along the MILC direction with (110) preference. The strain shift of Ge dots reveals the formation of high quality interface between the crystallized Si and Ge dot.     

Chemical analysis of NiAlFe thin films sputter deposited onto sapphire substrates

NiAlFe thin films were prepared onto sapphire single crystals by physical vapour deposition (PVD) and these were analysed by X-ray photoelectron spectroscopy (XPS) in combination with argon ion etching to determine the composition depth profile and interfacial characteristics of the samples. Non-linear least square fitting (NLLSF) analysis of the data was required due to the conflict of several peaks of interest. XPS depth profiles show that, for non-annealed NiAlFe–Al₂O₃, the interface is sharp and oxygen diffusion occurs at different annealing temperatures. Ni remains chemically unaffected by the presence of oxygen while the formation of aluminium oxide compounds occur. Two iron species are present in the film thickness where the low binding energy component is attributed to Fe–Fe or Fe–Al interactions and the higher one to the NiAlFe compound. The reduction-dissolution of the sapphire substrate leads to depletion of oxygen in the sapphire surface layer and the formation of alumina at the NiAlFe–Al₂O₃ interface. Within the film, aluminium and nickel are present as an intermetallic compound. Annealing of the samples induces surface oxidation and the subsequent formation of an Al₂O₃ layer. This type of interphase morphology should lead to optimal fibre/matrix (F–M) adhesion, and therefore optimal load transfer between the matrix and reinforcement.     

三价铈离子掺杂氯化钾的光致发光性能

采用水热蒸发法制备了KCl∶Ce3+荧光粉。测量并分析了材料在室温下的真空紫外激发光谱及相应的发射光谱。结果表明激发谱显示6个峰,峰位分别为149、194、206、219、233和251nm。其中149nm的激发峰是基质吸收引起的;194、206、219、233和251nm是Ce3+离子的4f→5d跃迁引起的。发射峰显示双峰结构,峰位分别是311和326nm。此峰对应于Ce3+离子的5d→4f(2F5/2,2F7/2)跃迁。