The analysis of broadened x-ray diffraction profiles provides a useful insight into the structural properties of materials, including crystallite size and inhomogenous strain. In this work a general method for analysing broadened x-ray diffraction profiles is developed. The proposed method consists of a two-fold maximum entropy (MaxEnt) approach. Conventional deconvolution/inversion methods presently in common use are analysed and shown not to preserve the positivity of the specimen profile; these methods usually result in ill-conditioning of the solution profile. It is shown that the MaxEnt method preserves the positivity of the specimen profile and the underlying size and strain distributions, while determining the maximally noncommital solution. Moreover, the MaxEnt method incorporates any available a priori information and quantifies the uncertainties of the specimen profile and the size and strain distributions. Numerical simulations are used to demonstrate that the MaxEnt method can be applied at two levels: firstly, to determine the specimen profile, and secondly to calculate the size or strain distribution, as well as their average values. The simulations include both sizeand strain-broadened specimen profiles. The experimental conditions under which the data is recorded are also simulated by introducing instrumental broadening, a background level and statistical noise to produce the observed profile. The integrity of the MaxEnt results is checked by comparing them with the traditional results and examining problems such as deconvolving in the presence of noisy data, using non-ideal instrument profiles, and the effects of truncation and background estimation in the observed profile. The MaxEnt analysis is also applied to alumina x-ray diffraction data. It is found that the problems of determining the specimen profile, column-length and strain distributions can be solved using the MaxEnt method, with superior results compared with traditional methods. Finally, the issues of defining the a priori information in each problem and correctly characterising the instrument profile are shown to be critically important in profile analysis.

vi, 165 leaves : ill., appendices / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1972) from the Dept. of Physics, University of Adelaide

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In this thesis, we discuss the structural properties and quality of GaN-based material structures grown on sapphire¡BLAO and silicon substrates by X ray diffraction pattern. According to 2theta scan, we estimate the Al and In concentration in AlGaN and InGaN films. The thickness of InGaN/GaN multiple quantum wells can also be got from 2

Abstract:omitted

Abstract As integrated circuit dimensions continue to shrink, interconnect RC delay becomes an increasingly serious problem. Fabrication of interconnect structures using new materials of low resistivity and low permittivity to replace the traditional Al and SiO2 interconnect technology is in high demand. Specially, copper and low dielectric constant (low-k) polymers show great promise. Among various low-k materials, spin-on glass (SOG) materials have been widely used as an interlayer dielectric in multilevel interconnections because they are applied easily and have relatively low process costs. One class of materials, which offers many of properties of silica (SiO2) hardness, thermal and dimensional stability etc.) are the HOSP (Hybrid Organic-Siloxane-Polymer)and HSQ (Hydrogen Silsesquioxane) represent an important member of this family. HOSP and HSQ exhibits a relatively low dielectric constant (k=2.6-2.8) as compared to SiO2 (k=4.0).It is intrinsically hydrophobic, has reasonable mechanical hardness, and possesses exceptional thermal and dimensional stability (in excess of 400¢J). For these reasons, HOSP and HSQ represent an excellent candidate for applications on the multilevel interconnect architecture. On the other hand, etching and PR removal are key technology during the manufactures of multilevel interconnects. X-ray lithography process is adopted to avoid these issues. As a result, a novel X-ray lithography technology for the low-k interlayer has been proposed for fabrication of IC. And it is a low cost process. In this work, the characteristics of PR removal have been investigated. Experimental results have shown that the dielectric properties of HOSP and HSQ are degraded by PR removal process. The X-ray exposure will solve these problems and it will be a useful tool in advance ICs fabrication. The advantage of the X-ray exposure is the direct patterning, avoids the issues during the etching and photoresist striping processes. The part of film exposed by X-ray will be cured and the other part could be dissolved with the solvent. Strictly speaking, these two issues will be overcome by the X-ray curing.

Thèse de doctorat : Science et ingénierie des matériaux : INPL : 2007. / Titre provenant de l'écran-titre.

Reproduction de : Thèse doctorat : Physique : Université de Cergy-Pontoise : 2006. / Titre provenant de l'écran titre. Bibliogr. p.231-236. Index.

Thesis (Ph. D.)--Open University. BLDSC no. DXN033653.

Thesis (Ph. D.)--Lehigh University, 2003. / Includes vita. Includes bibliographical references (leaves 194-209).