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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Synthesis and Characterization of Transition Metal Complexes as well as their Application in the Formation of Metal-based Materials and the Investigation of their (Spectro)Electrochemical Behavior

Preuß, Andrea 30 July 2020 (has links)
This Ph.D. thesis concentrates on the synthesis and characterization of tailor-made metal-based precursors and their application in the metal-organic chemical vapor deposition (MOCVD), combustion chemical vapor deposition (CCVD) and in the spin-coating process. Therefore, different complexes containing copper, ruthenium, palladium and gold were synthesized and investigated concerning their thermal properties, especially their decomposition behavior and volatility. Copper(II) and palladium(II) β-ketoiminates were synthesized and used in MOCVD or spin-coating deposition experiments for the formation of metal and metal oxide materials. Ruthenium complexes of type Ru(CO)2(PEt3)2(O2CR)2 (R = Me, Et, iPr, tBu, CH2OMe, CF3) were investigated concerning their physical characteristics depending on the different carboxylates. While primarily focusing on the thermal decomposition behavior, VT IR (variable temperature infrared) spectroscopy, TG-MS (thermogravimetry-mass-spectrometry) studies and DFT (density-functional theory) calculations were carried out to gain a deeper inside into the degradation of the respective complexes, whereby it was possible to propose decomposition mechanisms. Furthermore, from these results it was possible to propose decomposition mechanisms. Gold carboxylates of type [AuO2CCH2OMe(PR’3)] (R’ = Et, nBu) were synthesized and characterized for the use as precursors within CCVD processes to generate Au and SiOx:Au materials. The deposits were used as heterogeneous catalyst in the reduction of 4-nitrophenol. The deposition behavior of zinc diolate towards zinc oxide layer formation was studied by MOCVD experiments, whereby an influence on the crystallinity of the received films was observed depending on the deposition conditions. The second part of this dissertation focuses on the synthesis of polyaromatic hydrocarbons (napthalene, phenanthrene and pyrene) functionalized with Fc (Fc = Fe(η5-C5H4)(η5-C5H5)) units as redox-active group. Thereby, the main emphasis was on the investigation of the charge transfer properties between the ferrocenyl entities through the π-conjugated bridges. The charge transfer behavior was affected by the substituents or substitution pattern at the aryls resulting in more or less intense intervalence charge transfer (IVCT) excitations of the respective compounds. In order to explore the interaction between the Fc-functionalized arenes and SWCNTs (single-walled carbon nanotubes), these molecules were studied by single-crystal X-ray diffraction analysis and DFT calculations. Moreover, disentangling experiments of SWCNTs with a Fc-functionalized pyrene led to the formation of a novel nanoconjugation, whereby the electrochemical response of the ferrocenyl entities is still present. / Die vorliegende Arbeit befasst sich mit der Synthese und Charakterisierung von maßgeschneiderten Übergangsmetall-basierten Precursoren und deren Anwendung in der metallorganischen chemischen Gasphasenabscheidung (MOCVD), in der Flammenbeschichtung (CCVD), oder in der Rotationsbeschichtung. Dafür wurden Kupfer-, Ruthenium-, Palladium- und Gold-haltige Komplexe hergestellt und bezüglich ihrer thermischen Eigenschaften, insbesondere das Zersetzungsverhalten und die Flüchtigkeit, charakterisiert. Cu(II)- und Pd(II)-β-Ketoiminate wurden synthetisiert und in der MOCVD oder in der Rotationsbeschichtung genutzt, um metallische und metalloxidische Materialien abzuscheiden. Ruthenium Komplexe des Typs Ru(CO)2(PEt3)2(O2CR)2 (R = Me, Et, iPr, tBu, CH2OMe, CF3) wurden hinsichtlich ihrer physikalischen Eigenschaften in Abhängigkeit der verschiedenen Substituenten der Carboxylate untersucht. Dabei lag der Fokus im Besonderen auf der thermischen Zersetzungen, welche mittels VT IR (variable Temperatur-Infrarot) Spektroskopie, TG-MS (Thermogravimetrie-Massenspektrometrie) Untersuchungen und DFT (Dichtefunktionaltheorie) Berechnungen genauer beleuchtet wurden. Dabei war es anhand der erhaltenen Ergebnisse möglich Zersetzungsmechanismen zu formulieren. Weiterhin wurden Goldcarboxylate der Art [AuO2CCH2OMe(PR’3)] (R’ = Et, nBu) synthetisiert und in der CCVD untersucht, um Au und SiOx:Au Materialien herzustellen, welche im Weiteren als heterogene Katalysatoren für die Reduktion von 4-Nitrophenol genutzt wurden. Das Abscheideverhalten von Zinkdiolaten in der MOCVD zur Erzeugung von dünnen Zinkoxidfilmen wurde beispielsweise in Hinblick des Einflusses auf die Kristallinität der Filme untersucht. Im zweiten Teil der Dissertation wird die Synthese von Fc-funktionalisierten (Fc = Fe(η5-C5H4)(η5-C5H5)) polyaromatischen Kohlenwasserstoffen (Naphthalen, Phenanthren, Pyren) diskutiert. Der Schwerpunkt lag dabei auf der Untersuchung des Elektrontransferverhaltens zwischen den Redox-aktiven Gruppen in Abhängigkeit der Substituenten und des Substitutionsmusters der π-konjugierten Brücke. Diese Verbindungen wurden mittels Röntgeneinkristallstrukturanalyse und DFT-Berechnungen untersucht um festzustellen, ob eine Wechselwirkung zwischen den Fcfunktionalisierten Arenen und SWCNTs (einwandige Kohlenstoffnanoröhren) möglich ist. Entbündelungsversuche von SWCNTs in Anwesenheit eines Fc-funktionalisierten Pyrens lieferten ein neuartiges Hybridsystem, welches Fc-basierte Redoxprozesse zeigte.
12

ALD of Copper and Copper Oxide Thin Films For Applications in Metallization Systems of ULSI Devices

Waechtler, Thomas, Oswald, Steffen, Roth, Nina, Lang, Heinrich, Schulz, Stefan E., Gessner, Thomas 15 July 2008 (has links)
As a possible alternative for growing seed layers required for electrochemical Cu deposition of metallization systems in ULSI circuits, the atomic layer deposition (ALD) of Cu is under consideration. To avoid drawbacks related to plasma-enhanced ALD (PEALD), thermal growth of Cu has been proposed by two-step processes forming copper oxide films by ALD which are subsequently reduced. This talk, given at the 8th International Conference on Atomic Layer Deposition (ALD 2008), held in Bruges, Belgium from 29 June to 2 July 2008, summarizes the results of thermal ALD experiments from [(<sup><i>n</i></sup>Bu<sub>3</sub>P)<sub>2</sub>Cu(acac)] precursor and wet O<sub>2</sub>. The precursor is of particular interest as it is a liquid at room temperature and thus easier to handle than frequently utilized solids such as Cu(acac)<sub>2</sub>, Cu(hfac)<sub>2</sub> or Cu(thd)<sub>2</sub>. Furthermore the substance is non-fluorinated, which helps avoiding a major source of adhesion issues repeatedly observed in Cu CVD. As result of the ALD experiments, we obtained composites of metallic and oxidized Cu on Ta and TaN, which was determined by angle-resolved XPS analyses. While smooth, adherent films were grown on TaN in an ALD window up to about 130°C, cluster-formation due to self-decomposition of the precursor was observed on Ta. We also recognized a considerable dependency of the growth on the degree of nitridation of the TaN. In contrast, smooth films could be grown up to 130°C on SiO<sub>2</sub>and Ru, although in the latter case the ALD window only extends to about 120°C. To apply the ALD films as seed layers in subsequent electroplating processes, several reduction processes are under investigation. Thermal and plasma-assisted hydrogen treatments are studied, as well as thermal treatments in vapors of isopropanol, formic acid, and aldehydes. So far these attempts were most promising using formic acid at temperatures between 100 and 120°C, also offering the benefit of avoiding agglomeration of the very thin ALD films on Ta and TaN. In this respect, the process sequence shows potential for depositing ultra-thin, smooth Cu films at temperatures below 150°C.

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