EDX depths analysis of MIS-structures

Based on experimental energy transfer distributionsdE/dx including the X-ray depth distribution function (x,E ₀,Z) an effective-layer method has been developed in order to homogenize a multilayer target. Effective layer thicknesses are related to real layer thicknesses by means of equal transmission-energy rates. This method has been proved by EDX measurements of Au-SiO₂-Si structures showing good agreement with the real structures.Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday     

Accuracy of film thickness determination in electron probe microanalysis

The thickness of copper films (100–450 nm) on silicon substrates was determined by electron probe microanalysis (EPMA) applying (z) procedures of Pouchou and Pichoir. Film thickness was calculated from experimental k-ratios analyzed with electron energies between 6 and 30 keV using commercial software (LAYERF distributed by CAMECA). The influence of the incident electron energy and X-ray line chosen for analysis on the results was investigated. Accuracy of film thickness determination was evaluated by comparison with Rutherford backscattering spectroscopy (RBS) and secondary ion mass spectrometry (SIMS). The difference between layer thicknesses determined with EPMA and RBS is in general less than 2%, if EPMA measurements are performed with various electron energies. Layer thicknesses determined with Cu-L are mostly closer to values obtained by RBS than those derived from Cu-K radiation. Preliminary SIMS measurements yielded inconsistent results and, thus, cannot be used in this case to determine the layer thickness of Cu films on Si accurately.     

X-Ray Emission from Thin Films on a Substrate – Calculation and Experiments

 Monte Carlo simulation of electron transport in solids is widely used in electron microscopy, spectroscopy and microanalysis. The reliability of physical models incorporated in a Monte Carlo code is usually checked by comparing with experimental results. Elastic or inelastic collisions are usually considered as the basic interactions of electrons with atoms. In our Monte Carlo code the single scattering model is employed for simulation of X-ray emission from thin films of Au on the Si substrate. The electron beam energy was in the range 10–30 keV, the take-off-angle was 40°. The simulated values of X-ray production were calculated in our Monte Carlo code using several models of ionisation cross-sections. For the emitted intensities the depths of inelastic collision and X-ray absorption were taken into account, then the k-ratios were calculated. These data were compared with experimental values of k-ratios calculated from X-ray intensities of Au M and Au L characteristic lines. We followed mainly the dependence of the k-ratios of the film element on film thickness. The film thickness was in the range 0.05–1 μm. Reasonably good agreement was found for dependences of X-ray intensity on film thickness in the whole energy range and for both lines, especially for Powell’s model of the ionisation cross-section.     

桑蚕丝腺体和丝纤维中金属离子的含量

用不同的测试方法, 即质子诱导X射线发射(PIXE)、电感耦合等离子体质谱(ICP-MS)和原子吸收光谱(AAS)对桑蚕丝腺体和丝纤维中金属元素的含量进行了详细的表征. 结果表明, 在桑蚕丝腺体和丝纤维中含有钠、镁、钾、钙、铜、锌、铁、锰八种金属元素, 同时还可能含有微量的铷和锶. 这些金属元素在丝腺体和各种丝纤维(蚕茧丝、强拉丝和脱胶丝)中的含量都有所变化, 而这些变化可能与之在成丝过程(丝蛋白的构象转变过程)中所起的作用有关.     

有机金属化合物中碳氢钼(锌)同时快速微量测定研究

由于某些有机金属化合物很不稳定,制取困难,获得量甚少,因此迫切需要建立相应的快速分析方法,并尽可能利用一份样品测出多种元素含量,以判断化合物的组成或纯度。虽然有机金属化合物(包括原子簇化合物)中碳、氢和金属的同时快速测定法已有报道,但是,某些有机钼(锌)化合物在高温燃烧氧化过程中,能生成挥发性的金属氧化物,并随着载气吹离样品舟,故不能简单地以高温氧化分解和称样品舟中残渣的方法来进行快速同时测定。本文对Gawargious等人建     

New external reagents for the simultaneous microdetermination of carbon,hydrogen and mercury

Non-conventional, extremely cheap and readily available materials, namely zinc plates, pumice granules or polystyrene foam cubes, have been utilized as new external mercury-retentive agents at room temperature for the simultaneous gravimetric microdetermination of mercury, carbon and hydrogen by the rapid straight empty-tube method of Korshun and Klimova. A standard Pregl absorption tube charged with the reagent is connected between the combustion tube and the water-absorption tube. Satisfactory results are obtained for carbon, hydrogen and mercury, and compare reasonably well with those found by using the traditional silver wool or gold sponge under similar conditions. Sulphur or halogen can also be determined simultaneously, as usual.     

TLC－FTIR联用方法的应用

本文利用TLC-FTIR联用技术在Analect公司出品的RFX-65型PTIR仪上，检测了未知混合物样品A的四种组份，未知样品B的两个组份，以及对3微克和5微克标样的均三硝基苯(1，3，5-TRINITROBENZENE)进行测定，均得到了可以认可的红外光谱图。本方法操作较简便且灵敏，但功能的应用范围有待开发。     

Standardless quantitation of thin film specimens

This paper reviews the procedures available for the X-ray microanalysis of specimens in the form of thin self-supporting films without the use of standards. Standardless analysis refers to the procedure in which there is no requirement to prepare standards and then measure them during the course of the current analysis. The factors by which the measured X-ray intensities are converted to compositions are calculated for the elements of interest after the experimental measurements have been completed. These calculations are based on published tabulated data for the physical constants required, or evaluated from theoretical or empirical models. The physical parameters which are required to evaluate the characteristic X-ray production in the specimen are the fluorescence yield, the partition function and the X-ray production cross-section. Most analytical procedures ensure that other variables such as the specimen thickness and electron beam current are not required. Of the parameters mentioned, the first two have been examined and extensively tabulated in the literature. This paper focuses primarily on methods of evaluating the X-ray cross-sections for both the characteristic and bremsstrahlung production.The way in which the physical parameters are incorporated into the standardless quantitation methods for materials samples is described. A new standardless version of the continuum normalisation method for quantitative analysis for samples with organic matrices is introduced. Some techniques for making corrections for absorption to the observed intensities are discussed, and formulae are given for X-ray absorption and fluorescence which it may be necessary to use with thicker specimens.     

High-Spatial-Resolution Low-Energy Electron Beam X-Ray Microanalysis

 Performing X-ray microanalysis at beam energies lower than those conventionally used (< 10 keV) is known to significantly improve the spatial resolution for compositional analysis. However, the reduction in the beam energy which reduces the X-ray interaction diameter also introduces analytical difficulties and constraints which can diminish the overall analytical performance. This paper critically assesses the capabilities and limitations of performing low beam energy, high spatial resolution X-ray microanalysis. The actual improvement in the spatial resolution and the reduction in the X-ray yield are explored as the beam energy is reduced. The consequences for spectral interpretation, quantitative analysis and imaging due to the lower X-ray yield and the increased occurrence of X-ray line overlaps are discussed in the context of currently available instrumentation.     

聚二甲基硅氧烷芯片自由酶反应器检测葡萄糖

应用电泳中介微分析(EMMA)技术,构建聚二甲基硅氧烷(PDMS)芯片自由酶反应器, 在线检测葡萄糖(Glu),在十字形的芯片通道上,采用自制的碳纤维微电极检测葡萄糖氧化酶(GOD)催化氧化Glu生成的H2O2,并对检测电位、GOD浓度、GOD进样时间、分离电压等参数进行了优化,测定了该自由酶反应器的线性范围和检出限,考察了其重现性及稳定性.结果表明,此自由酶反应器制作方便,操作简单,重现性好,Glu浓度在0.1～20 mmol/L之间有较好的线性关系(r=0.997),检出限为19.8 μmol/L(S/N=3).