Surface analysis, special techniques

Ti - N stoichiometry in contact holes in advanced integrated circuits has been studied by Pamler and Kohlhase [143]. Since the holes are themselves of 2-3-pm diameter, analysis of their interior surface requires special techniques. 

The detection of impurities or surface layers (e.g., oxides) on thick specimens is a special situation. Although the X-ray production and absorption assumptions used for thin specimens apply, the X-ray spectra are complicated by the background and characteristic X rays generated in the thick specimen. Consequently, the absolute detection limits are not as good as those given above for thin specimens. However, the detection limits compare very favorably with other surface analysis techniques, and the results can be quantified easily. To date there has not been any systematic study of the detection limits for elements on surfaces however, representative studies have shown that detectable surface concentrations for carbon and... 

The most widely used techniques for surface analysis are Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS), Raman and infrared spectroscopy, and contact angle measurement. Some of these techniques have the ability to determine the composition of the outermost atomic layers, although each technique possesses its own special advantages and disadvantages. 

Brands proposed a calculation method in the case of segregation A special type of inhomogeneous, particulate objects is the surface analysis by microscopic techniques e.g. analytical electron sj troscopy, laser induced mass spectroscopy or proton-induced X-ray emission. Here the minimum sample size can be translated into the minimum number of specific sample points in the specimen under investigation. 

Th,s book compiles and describes much of the recent growth in developments and techniques in the fields of surface science and surface analysis. In the past decade, techniques, once mainly of interest to academia, have been adapted to solve a variety of industrial research and development problems. Advanced surface-characterization methods have moved quickly out of the research laboratory and into commercial instrument manufacture. Indeed, this growth has generated a highly specialized, even bewildering, array of techniques—an alphabet soup of techniques in fact. 

Surface Electrochemistry is an important field in Surface Science, which is undergoing a very important development. In spite of the complexity of the systems, the experimental measurements have acquired a very high degree of sophistication and atomic resolution has almost been reached. After the development of special techniques that allowed the preparation of well defined single crystal electrodes [1, 2], attempts have been made to use surface analysis techniques in an electrochemical environment. However, one must... 

Some special precautions are vital. XPS, being a surface analysis technique, is extremely sensitive towards surface contamination. Therefore, the sample has to be analyzed in a ultra high vacuum, which preserves its initial surface composition. 

IR spectroscopy is a common analytical technique in the textile industry. IR is capable of identifying fibers and their additives, as well as showing quantitative blend ratios and additive contents. The ATR (attenuated total reflection) technique, especially in its multiple form, MIR (multiple internal reflection) is of special importance in this field. The sample preparation is simple and fast the cut out swatches with appropriate surface areas are placed against each side of the MIR crystal, ensuring sufficient and uniform contact across the crystal surface. The internal reflection methods are non-destructive, so that the sample may be saved for other types of analysis, they are, further, methods of surface analysis. This is advantageous in all cases where the finish resides primarily on the fiber surface. In this case, a very strong spectrum of the finish is obtained, with minimal interference from the base fiber (Hannah et al., 1975). 

Many techniques have been used to detect the presence of poisons on metal surfaces, particularly by chemical analysis, but the effectiveness decreases with the poison content and special techniques become necessary for traces. For instance, special analytical (gas chromatography) capabilities to measure S concentrations below 5 ppb and CH4 below 1 ppm must be on-line (253). The sensitivity of spectroscopic methods becomes in those cases an important advantage. IR has often been employed to detect surface and/or bulk species by means of their character-... 

When the elements of interest in a specimen occur at extremely low concentrations, or when the available amount of material in a specimen is very small, it is desirable to apply the special techniques of trace analysis. In most fluorescence spectrometers the analyzed area on the surface of the specimen is designed to be approximately 5 cm. If the specimen is larger in area than this sensitive region and is much thicker than the thickness yielding 99% of the emitted x-ray intensity, then it can be considered to be of infinite dimensions. Many of the quantitative models and analysis techniques have been developed for this type of specimen. Occasionally, it is necessary to analyze a specimen which is thin compared to the 99% yield thickness or a specimen which cannot cover the total sensitive area of the fluorescence spectrometer. This type of specimen is considered to be of limited quantity. More frequently, specimens of unlimited quantity are available, but several or all of the elements of interest are present at trace concentration levels. 

With the enormous and increasing importance of surfaces to modern technological processes, a large number of techniques have been developed to study various surface properties. Here we consider only those techniques that have emerged to be most widely applicable to ceramic powders. Readers interested in the more specialized techniques are refared to texts devoted to surface analysis (23-25). 

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