基于FIB-SEM制备尖晶石微米颗粒的球差校正透射电镜样品

针对尖晶石微米颗粒材料,利用聚焦离子束扫描电镜双束系统(FIB-SEM),在传统透射电镜样品制备方法的基础上进行技术性改进,成功制备了高质量的球差校正透射电镜样品.并利用球差校正透射电镜成功观察到了尖晶石颗粒的截面原子结构,为更深入地研究尖晶石材料的结构和性能奠定了基础.     

金属玻璃微观形貌对晶化过程的影响

使用电解双喷法制备了金属玻璃中的环状和带状结构,利用扫描透射电子显微镜(STEM)、X射线能谱(EDS)和电子能量损失谱(EELS)等手段,没有发现明显的相分离现象,证实这些结构主要是样品厚度起伏导致的衬度变化。进一步原位退火实验表明,这些环状或条带状结构在加热后发生了明显地相分离,其中Ni和Cu元素聚集在厚区和薄区的交界处,产生了明显的偏聚现象,而Al的偏聚现象并不明显。这表明金属玻璃中的微观结构形貌可以显著地影响金属玻璃在晶化过程的相分离,局域偏析可能与Cu和Ni在厚区与薄区交界处优先成核有关,同时表面扩散速率与体扩散速率的差异也是导致晶化后元素浓度变化的原因之一。     

聚焦离子束制备透射电子显微镜样品的两种厚度判断方法

透射电镜样品的厚度是透射电镜(TEM)表征中一个重要参数,快速准确地判断样品厚度是制备高质量样品的前提.本文通过使用聚焦离子束(FIB)制备了带有厚度梯度的透射电镜样品(Si、SrTiO3和LaAlO3),并提出两种制样过程中快速判断厚度的方法.第一种通过扫描电子显微镜(SEM)的衬度变化经验地判断样品的厚度;第二种是用FIB在样品边缘切一个斜边,通过SEM测量斜边侧面的宽度用几何方法推断样品的厚度.这两种方法都通过会聚束电子衍射(CBED)和电子能量损失谱(EELS)测量的厚度作为检验标准.对比认为,样品较薄时用SEM衬度测厚比较合适;样品比较厚时用几何方法测量比较直接.     

FIB加工、扫描及透射电子显微镜相结合的复杂合金相层状组织表征北大核心CSCD

扫描电子显微镜(SEM)与聚焦离子束(FIB)可集成为双束系统,实现微区形貌观察与样品加工一体化,同时也可实现截面薄样品的定位提取。利用该技术并结合透射电镜(TEM)技术研究了Al-Pd-Fe复杂合金系铸态组织中层片结构的构成与分布特征。结果表明,铸态Al_(75)Pd_(15)Fe_(10)合金中的层片组织由M-Al_(13)Fe_4相与准晶相构成。通过对比发现,相同层片组织在背散射电子像与透射电镜观察下呈现出明显不同的分布特征。结合扫描与透射电子显微学成像原理,阐明了SEM和TEM两种表征方式产生不同结果的原因,指出了通过SEM,FIB以及TEM相结合对表征微细多相混合组织真实三维空间分布特征的必要性和有效性。     

微波作用下碳灰颗粒的形貌变化

强辐射激光已被发现可使纳米碳灰颗粒内部发生快速的结构变化,甚至可用来直接制备出洋葱状的巴基葱.研究了作用面更广的辐射场,即微波与碳灰纳米颗粒之间的相互作用.以金属基底作辅助,发现玻璃真空腔中的样品在微波照射下亦出现快速的内部结构变化,并呈现出洋葱状的多缺陷巴基葱.利用高分辨透射电镜和气体发光等手段研究了这一变化过程,发现C2分子仍为这一过程中的最小基本单元,这为该结构的变化机理提供了有效依据.     

用离子束混合及快速热处理方法形成钽的硅化物

本文描述用离子束透过钽金属膜进行混合和快速热处理方法来形成钽的硅化物.用溅射方法在P型硅衬底上淀积一层金属钽,然后用砷离子束透过钽金属模进行混合,采用快速热处理后形成了平整的硅化钽薄层.使用厚度为500埃的钽金属膜,得到钽的硅化物薄层电阻为5.5Ω/□.研究了砷离子能量、剂量及钽膜厚度对钽的硅化物薄层电阻的影响.用透射电镜和台阶仪对所形成的硅化钽进行了分析和厚度测量.     

低能离子束诱导蓝宝石自组织纳米结构与光学性能研究

针对蓝宝石有序纳米结构的制备,使用微波回旋共振离子源,研究了低能Ar+离子束在不同参数下刻蚀蓝宝石(C向)表面形成的自组织纳米结构及其光学性能。结果表明,当离子束入射能量为1200 e V、束流密度为265μA/cm2时,随着入射角度的增大(5°~40°),样品表面出现点状自组织纳米结构,该结构的有序性较差;当增加角度到45°时,样品表面出现了有序的条纹结构,在45°~70°时,增大离子束入射角度,样品表面沿离子束入射方向出现柱状结构,而在垂直于离子束入射方向,样品表面呈现出有序的条纹结构;随着离子束入射角度的增加,样品表面的纳米条纹结构的特征波长先减小(45°~60°)后逐渐增大(60°~70°),在60°附近,特征波长达到极小值,约为21.1 nm。在70°~75°时,样品表面呈现纵横比较大的纳米点状结构。增加离子束的作用时间,样品表面的纳米结构纵向尺寸增大,有序性增加,但纳米结构横向周期基本不变。有序纳米结构的出现使得样品的透射率得到提升。自组织结构变化是溅射粗糙化和表面驰豫机制相互作用的结果。     

硬质材料超薄切片机的研制

这种超薄切片机是一台装有薄型金刚石切割片的超低速切割机,它适用于钢铁、陶瓷、玻璃、单晶硅、骨骼、牙齿等硬质材料的试样切割。具有切割速度低;切割过程发热少;切削应力低;对试样的组织结构影响小等优点,并且刀口小,光洁度高,节省材料,试样切割最小厚度可达0.1～0.2mm,为超薄样品的制备提供了一台较理想的设备。尤其适用于透射电镜薄膜样品的制备。     

对称金属包覆结构中反射光干涉效应的研究

提出了一种可同时达到高对比度和高反射率的对称金属包覆结构。由于导波层的厚度是亚毫米量级,使该结构可容纳一系列共振模。利用四层波导菲涅耳公式,详细分析了耦合金属层的厚度对耦合效率的影响,给出了反射光达到最大对比度时耦合金属层厚度的最优值,并从物理的角度解释了这种现象产生的原因是对称金属包覆结构中的辐射损耗和本征损耗共同作用的结果。实验测量了对称金属包覆结构中反射光的干涉效应。结果表明,对称金属包覆结构可以大大增强反射光的干涉条纹中明、暗光线的对比度,同时光入射到对称金属包覆结构中的耦合效率可接近100%。这将有助于研究高对比度高反射率薄膜和基于对称金属包覆结构的传感器。     

蓝宝石表面纳米结构随杂质靶距离的演化

使用微波回旋共振离子源刻蚀蓝宝石（C向）表面，引入金属不锈钢杂质，研究了不同靶距处蓝宝石表面自组织纳米结构的演化规律及光学性能。采用原子力显微镜来观察样品表面的形貌变化，Taylor Surf CCI 2000白光干涉表面测量仪测量蓝宝石样片表面的粗糙度；选择X射线光电子能谱对样品表面的化学成分进行了表征。实验结果表明:当离子束能量为1000 eV，束流密度为487 μA/cm2，入射角度为65°，刻蚀时间为60 min，蓝宝石样片与杂质靶距离从1 cm增加到4 cm时，样片表面出现岛状结构并逐渐演变为连续的条纹结构。同时，自组织纳米结构随靶距增加，有序性增加，纵向高度逐渐减小，空间频率基本不变。刻蚀后样品表面的金属杂质残留很少，微结构的形成对蓝宝石具有增透作用。在离子束溅射过程中，岛状结构的出现促进了样品表面条纹纳米结构的生长，破坏了纳米结构的有序性。     

Comparison of TEM specimen preparation of perovskite thin films by tripod polishing and conventional ion milling

In this article, the effects of the transmission electron microscopy (TEM) specimen preparation techniques, such as ion milling and tripod polishing on perovskite oxides for high-resolution TEM investigation, are compared. Conventional and liquid nitrogen cooled ion milling induce a new domain orientation in thin films of SrRuO(3) and LaFeO(3) grown on (001)-oriented SrTiO(3) substrates. This is not observed in tripod-polished specimens. Different ion milling rates for thin films and substrates in cross-section specimens lead to artefacts in the interface region, degrading the specimen quality. This is illustrated by SrRuO(3) and PbTiO(3) thin films grown on (001)-oriented SrTiO(3). By applying tripod polishing and gentle low-angle, low-energy ion milling while cooling the sample, the effects from specimen preparation are reduced resulting in higher quality of the TEM study. In the process of making face-to-face cross-section specimens by tripod polishing, it is crucial that the glue layer attaching the slabs of material is very thin (<50 nm).     

透射电子显微镜高压电源箱气体绝缘技术及充气工艺

本文通过比较高压系统常用气态绝缘介质的性能,对比影响气体绝缘性能的关键参数,给出了透射电子显微镜高压电源箱绝缘材料的优化选择,介绍了六氟化硫(SF6)气体在透射电子显微镜高压电源绝缘中的应用,计算了充SF6绝缘气体的高压电源箱,并给出了透射电子显微镜高压箱的绝缘充SF6气体工艺.     

A high-quality cross-sectional transmission electron microscope specimen preparation technique for structural and interfacial property studies in microelectronic packaging

A new versatile procedure employing low-angle ion milling and a self-clamping titanium grid to produce high-quality cross-sectional transmission electron microscopy (TEM) specimens for microelectronic packaging structures is proposed. Large electron transparent areas are generated with minimal mechanical damage, ion-induced damage, differential thinning in inhomogeneous materials, and surface roughness. An application example on gold thermosonic wire bonds is demonstrated.     

Mechanical alloying of FeCo Nanocrystalline magnetic powders

Mechanical alloying of the Fe₅₀Co₅₀ equiatomic-magnetic alloy from elemental powders has been studied. Two milling speeds of 200 rpm and 300 rpm were used to process these powders. The as-milled powders were characterized using scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), x-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The mixing of Fe and Co was completed in 200 min at a milling speed of 300 rpm; however, an increase in saturation magnetization was observed up to 10-h milling, indicating an increase in compositional homogeneity as a function of milling time. These findings were also reflected in the XRD results. During the milling of Fe and Co at 300 rpm, an increase of powder size was observed after 100-min milling. Further milling at 300 rpm led to a reduction in powder size; the decrease of powder size was more effective when milling was conducted at 200 rpm. This was attributed to a difference in the milling mechanisms dominating at these two speeds. The TEM observation showed that a banded microstructure was observed in the as-milled powders. The banded structure consists of grains, many of which show texture effects. After further milling, the banded structure became finer, then randomly arranged, and finally disappeared.     

Al-Mg-Si-Cu合金中晶界和晶内析出相粗化规律的研究

采用显微硬度测试仪、扫描电镜和透射电镜观察及能谱分析,研究了Al-0.5Mg-1.0Si-0.8Cu(wt.%)合金的晶界析出规律和晶内析出相的粗化机制。结果表明:180℃时效处理的Al-0.5Mg-1.0Si-0.8Cu(wt.%)合金晶界处存在富Si相和Q相两类不连续分布的析出相,它们的尺寸分别约为1 mm和几十纳米;时效0.5 h时晶界处有少量富Si相,时效5 h时晶界富Si相明显增多,时效36 h时富Si相开始粗化且间距变大,再进一步时效其形貌和分布变化不大;晶界Q相与相邻晶粒铝基体的界面取向关系是:[510]Al//[1120]Q;时效36 h晶内开始出现粗化析出相,且随时效继续进行合金晶内析出大量粗化相,存在明显的晶界无析出带现象。晶内粗化析出相主要含有Si元素,呈片状、球状和棒状3种形貌。其中,棒状Si析出相是沿〈001〉Al方向生长的,且〈112〉Si//〈001〉Al,{111}Si//{010}Al。     

7150铝合金时效时晶界析出行为的研究

本文采用透射电子显微镜(TEM)、能谱分析(EDAX)对人工时效条件下晶界无析出带(PFZ)的演变规律进行研究.实验选用同一投影方向测量PFZ的宽度,结果表明PFZ的宽度对时效温度的敏感性远远高于对时效时间的敏感性.时效温度越高PFZ越宽,而在同一时效温度下PFZ的宽度并不随时效时间的延长而宽化.PFZ的宽度与相邻两个...     

基于透射电子显微镜TDX-200观察室的应力、应变分析

透射电子显微镜的观察室不仅要有便于观察、成像、照相等功能,还承载着电镜主体镜筒和电子枪的重量,因此观察室的设计与加工是镜筒主体制造的关键部分。本文以我国自主设计的TDX-200透射电子显微镜的观察室为研究对象,采用有限元结构分析软件ANSYS对其进行应力应变分析计算,为该类型的透射电子显微镜观察室设计和制造提供可靠数据。     

Improvements in performance of focused ion beam cross-sectioning: aspects of ion-sample interaction

A gallium (Ga) focused ion beam (FIB) has been applied increasingly to 'site-specific' preparation of cross-sectional samples for transmission electron microscopy (TEM), scanning TEM, scanning electron microscopy and scanning ion microscopy. It is absolutely required for FIB cross-sectioning to prepare higher-quality samples in a shorter time without sacrificing the site specificity. The present paper clarifies the parameters that impose limitation on the following performances of the FIB cross-sectioning: milling rate, cross-sectioning at a right angle with respect to the sample surface, curtain structures formed on the cross sections, ion implantation and ion damage. All of these are discussed from the viewpoint of ion-sample interaction. Improvements for these performances achieved by diminishing their limiting origins or by correcting the resultants are described. Especially, the FIB scanning speed is significantly utilizable to improve the milling rate. A microsampling method, which allows the FIB incidence in a sidewards or upwards direction as well as downwards with respect to the microsample surface, is very effective to minimize the curtain structures.     

Transmission electron microscopy and atom probe specimen preparation from mechanically alloyed powder using the focused ion-beam lift-out technique

The preparation of transmission electron microscopy (TEM) and atom probe-field ion microscopy (AP-FIM) specimens from mechanically alloyed Ti-Cu-Ni-Sn powder has been explored. Applying the focused ion beam (FIB) based in situ lift-out technique, it has been demonstrated that specimen preparation can be carried on single micrometre-sized powder particles without the use of any embedding media. Since the particles did not incorporate any micropores, as revealed by cross-sectioning, the standard procedure known for bulk samples could be simply implemented to the powder material. A sequence of rectangular cuts and annular milling was found to be a highly efficient way of forming a tip-shaped AP-FIM specimen from a square cross-section blank. A Ga level < or =1 at.% was detected if a low beam current of 10 pA was chosen for the final ion-milling stages. Implanted Ga ions were mostly confined to a zone of about 2 nm in thickness and indicated that ion-induced structural transformations were negligible.     

A review of focused ion beam technology and its applications in transmission electron microscopy

The role of focused ion beam (FIB) fabrication in the development of sample preparation techniques for transmission electron microscopy (TEM) has been described in this paper. Since the repeatability of FIB sampling and TEM observations has become important, the microsampling and in situ lift-out methods are currently in wide use. Furthermore, artifacts induced during FIB milling and the consequent difficulties with energy dispersive X-ray spectroscopy are detailed. The remarkably increased capability of scanning ion microscopy and its applications are also discussed.