Studies of copper-aluminum interfaces using glancing angle X-ray reflectivity and EXAFS.
Item
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Title
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Studies of copper-aluminum interfaces using glancing angle X-ray reflectivity and EXAFS.
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Identifier
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AAI9000020
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identifier
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9000020
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Creator
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Chen, Huaiyu.
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Contributor
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Adviser: A. C. Damask
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Date
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1989
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Language
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English
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Publisher
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City University of New York.
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Subject
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Physics, Condensed Matter
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Abstract
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Synchrotron radiation measurements using glancing angle X-ray reflectivity and fluorescence EXAFS were used to study Cu-Al thin film interfaces. The technique can detect small amounts of interfacial reaction ({dollar}\sim{dollar}10 to 20 A), which conventional techniques have difficulty detecting. The reflectivity data contain information about film morphology, and the EXFAS data give atomic bond types and distances. A combination of the two sets of data provides a picture of an interface. A major effort of this thesis is to convert the glancing angle EXAFS into a quantitative tool from a qualitative one. The first step is to develop analysis routines for the reflectivity data to extract a model of the concentration profile and roughness. Then the crucial step towards the goal can be made: The correction for the anomalous dispersion effect on the EXAFS data. Results obtained from Cu-Al interfaces prepared in an UHV environment with and without exposure to oxygen before Al deposition, are compared. The reactions caused by thermal annealing at temperatures ranging from 65 to 200{dollar}\sp\circ{dollar}C are also studied. The width of the interface region for the UHV(O) sample is estimated to be 35{dollar}\pm{dollar}25 A as prepared, and 75 {dollar}\pm{dollar} 25 A after the 140{dollar}\sp\circ{dollar}C anneal; for the UHV sample the width is estimated to be 110 {dollar}\pm{dollar} 30 A as prepared, and 175 {dollar}\pm{dollar} 40 A after the 140{dollar}\sp\circ{dollar}C anneal. Within the sensitivity of analysis, it was shown that the mixed region of both samples is not a single-phase compound, indicating the simultaneous growth of several phases. The low levels of reaction observed in this work are difficult to detect by other techniques, such as X-ray diffraction. Thus, the sensitivity of the glancing angle EXAFS technique is demonstrated and it should have many applications to other interface systems.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
