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Tertiary phosphine complexes of zirconium(IV) and hafnium(IV)Carter, Alan January 1985 (has links)
The tetra-halides of zirconium and hafnium were reacted with one equivalent of the potentially tridentate hybrid ligand, N(SiMe₂CH₂PR₂)2-, (R = Me, i-Pr, t-Bu) to generate the corresponding mono-ligand complexes MCl₃{N(SiMe₂CH₂PR₂)₂), (M = Zr, Hf). Based on the results obtained from the solution spectroscopic data and the single crystal X-ray diffraction analyses of HfCI₃{N(SiMe₂CH₂PMe₂)₂> and ZrCl₃{N(SiMe₂CH₂P(i-Pr)₂)₂) the stereochemistries of all the MCI ₃{N(SiMe ₂CH₂PR₂) ₂) complexes were found to be meridional in solution, but both facial and meridional geometries were displayed in the solid state dependent on the ligand.
The mono-ligand derivatives served as useful starting materials for the generation of zirconium- and hafnium-carbon bonds. Thus the addition of three equivalents of MeMgCl to one equivalent of MCl₃{N(SiMe₂CH₂PR₂)₂} generated the trimethyl complexes M(CH₃)₃{N(SiMe₂CH₂PR₂)₂}. When two equivalents of MeMgCl was added to the mono-ligand complexes, an inseparable mixture of the monomethyl and dimethyl derivatives was obtained. The stereochemistry of Hf(CH₃)₃{N(SiMe₂CH₂PMe₂)₂} is facial in the solid state but displays unusual fluxional behaviour in solution. This behaviour is observed for all the trimethyl derivatives as a consequence of the dissociative nature of the phosphine donors. Several possible rearrangement pathways for these compounds are discussed in an attempt to interpret this behaviour in solution. / Science, Faculty of / Chemistry, Department of / Graduate
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Characterization of solution-based inorganic semiconductor and dielectric materials for inkjet printed electronicsMunsee, Craig L. 14 June 2005 (has links)
The long-term goal of this research project is the development of solution-based
inorganic dielectric and semiconductor materials for inkjet printed electronics.
The main focus of this thesis involves testing of the materials and devices
under development.
A new solution-based inorganic dielectric material (HfOSO₄), given the
name hafsox, is developed and shows excellent dielectric properties. Hafsox with
the addition of lanthanum, to improve film dehydration, has successfully been
demonstrated as a gate dielectric. Metal-insulator-metal (MIM) capacitance testing
of hafsox with lanthanum, has resulted in a low loss tangent of 0.30% at 1
kHz, a relative permittivity of 11.47 at 1 kHz, a breakdown voltage of 6.30 MV
cm⁻¹, and a leakage current density of 4.38 nA cm⁻² at 1 MV cm⁻¹.
Progress has also been achieved in the development of solution-based semiconductor
materials. To date the most successful of these materials is zinc indium
oxide (ZIO), which has been demonstrated as a thin-film-transistor (TFT) channel
material. This ZIO TFT is a depletion-mode device with a turn-on-voltage
of V[subscript on]~ -19 V, a threshold voltage of V[subscript T] ~-16 V, and a drain current on-to-off
ratio of ~10³. Mobilities extracted from this ZIO TFT include an incremental
mobility of μ[subscript inc] ~0.05 cm² V⁻' sec⁻', an effective mobility of μ[subscript eff] ~0.02 cm²
V⁻' sec⁻', and an average mobility of μ[subscript avg] ~0.02 cm² V⁻' sec⁻' at V[subscript GS]=20 V.
The development of metal-semiconductor field-effect transistors (MESFET)
TFTs is also investigated as a means of eliminating the need for a dielectric
material in order to reduce the complexity of fabricating circuits. MESFETs are
attempted with semiconductor materials such as CdS that is deposited by chemical
bath deposition (CBD) and SnO₂ that is deposited by RF magnetron sputtering,
but with little success. The most successful MESFET-like device fabricated, employing
SnO₂ as the channel material, is a strong depletion-mode device with a
small amount of gate voltage modulation. / Graduation date: 2006
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Photoresist and ion-exchange chemistry of HafSOxTelecky, Alan J. 01 May 2012 (has links)
The chemistry of hafnium oxide based and materials are described in the context of ion exchange and lithography. HafSOx, represented by the composition HfO₂₋[subscript x](SO₄)x, is described to possess a significant capacity towards ion exchange in acidic and basic solutions, enabling films of HafSOx to be cleanly and readily be converted to oxide films by neutralization. The optical properties, composition and morphology of these oxide films are characterized. The fabrication of mixed metal oxide films is demonstrated via solution and ion exchange routes.
This thesis also explores the photoresist chemistry of HafSOx resists. A photoreaction mechanism based on the decomposition of peroxide is proposed. In addition, the patterning of HafSOx films by 193 nm, extreme ultraviolet (EUV) and electron beam radiation is described, and the influence of composition on its photoresist properties is studied. / Graduation date: 2012
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A study on the material and device characteristics of hafnium oxynitride MOSFETs with TaN gate electrodesKang, Changseok 28 August 2008 (has links)
Not available / text
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Processing and reliability studies on hafnium oxide and hafnium silicate for the advanced gate dielectric applicationChoi, Rino 28 August 2008 (has links)
Not available / text
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ANSA-bridged and binuclear metallocene compounds of zirconium and hafniumDiamond, Gary M. January 1994 (has links)
This thesis describes the synthesis and characterisation of new mononuclear and binuclear zirconium and hafnium compounds containing ansa-bridged ligands. Some olefin polymerization studies, employing the new compounds as catalysts, are also presented. <strong>Chapter 1</strong> begins with an introduction to Ziegler-Natta polymerization of olefins, concentrating on recently developed metallocene-based catalyst systems. The second part of the Chapter charts the development of group 4 ansa-metallocene derivatives, especially their use as stereospecific catalysts. Finally, a review of binuciear group 4 metallocene compounds containing bridging bis(cyclopentadienyl)-type ligands is presented. <strong>Chapter 2</strong> describes the synthesis and characterisation of some novel mononuclear metallocene compounds of zirconium and hafnium containing ansa-bridged ligands. The ansa-bridged mononuclear compounds [{Me<sub>2</sub>C(η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>)(η<sup>2</sup>-C<sub>9</sub>H<sub>6</sub>)}M(η<sup>5</sup>C<sub>5</sub>H<sub>5</sub>)Cl] (M = Zr, Hf), [{(CH<sub>2</sub>)<sub>5</sub>C(η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>)(η<sup>2</sup>-C<sub>9</sub>H<sub>6</sub>)}M(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Cl] (M = Zr, Hf) and [{Me<sub>2</sub>(η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>)(η<sup>3</sup>-C<sub>13</sub>H<sub>8</sub>)}Zr(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Cl] are described, along with the X-ray crystal structures of the zirconium compounds. The η<sup>2</sup>-indenyl and η<sup>3</sup>-fluorenyl coordination modes observed for these compounds are unprecedented. The synthesis and characterisation of the novel, mononuclear ansa-bridged compounds [{Me<sub>2</sub>C(η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>)<sub<2</sub>}M(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Cl] (M = Zr, Hf) is also described, along with their X-ray crystal structures. The variable temperature solid state <sup>13</sup>C CP/MAS NMR spectra of [{Me<sub>2</sub>C(η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>)<sub<2</sub>}M(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Cl] (M = Zr, Hf) show slow rotation of the C<sub>5</sub>H<sub>5</sub> ring on the NMR timescale. <strong>Chapter 3</strong> describes the synthesis and characterisation of some novel homo- and hetero-binuclear metallocene compounds of zirconium and hafnium in which the metals are bridged by an unsymmetrical ansa ligand. The novel, chiral homobinuclear compounds [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)MCl<sub>2</sub>{(η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>)CMe<sub>2</sub>(η<sup>5</sup>-C<sub>9</sub>H<sub>6</sub>)}MCl<sub>2</sub>(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)] (M = Zr, Hf) are described. The ansa-bridged mononuclear compounds [{Me<sub>2</sub>C(η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>)(η<sup>2</sup>-C<sub>9</sub>H<sub>7</sub>)M(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Cl] (M = Zr, Hf) are used as reagents for the selective synthesis of the heterobinuclear analogues [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)MCl<sub>2</sub>{(η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>)CMe<sub>2</sub>(η<sup>5</sup>-C<sub>9</sub>H<sub>6</sub>)}M*Cl<sub>2</sub>(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)] (M = Zr, M* = Hf ; M = Hf, M* = Zr) and the unsymmetrical homobinuclear compound [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)ZrCl<sub>2</sub>{(η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>)CMe<sub>2</sub>(��<sup>5</sup>-C<sub>9</sub>H<sub>6</sub>)}ZrCl<sub>2</sub>(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)]. The methylated derivatives [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)M(CH<sub>3</sub>)<sub>2</sub>{(η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>)CMe<sub>2</sub>(η<sup>5</sup>-C<sub>5</sub>H<sub>6</sub>)}M*(CH<sub>3</sub>)<sub>2</sub>(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)] (M = Zr, M* = Zr, Hf; M = Hf, M* = Zr, Hf) are also described. The structurally related mononuclear compounds [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)MCl<sub>2</sub>{(η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>)CMe<sub>2</sub>(C<sub>9</sub>H<sub>7</sub>)}] (M = Zr, Hf) and [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Zr(CH<sub>3</sub>)<sub>2</sub>{(η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>)CMe<sub>2</sub>(C<sub>9</sub>H<sub>7</sub>)}] have also been prepared. <strong>Chapter 4</strong> presents some olefin polymerization studies using the new compounds described in Chapter 3 as catalysts, along with either methylaluminoxane or the recently developed co-catalysts [Ph<sub>3</sub>C]<sup>+</sup>[B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>]<sup>-</sup> and B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>. <strong>Chapter 5</strong> provides the experimental details for the reactions described in this thesis and the characterising data for all new compounds are given in <strong>Chapter 6</strong> Crystallographic data for the for the X-ray structure determinations in Chapter 2 are given in the <strong>Appendices</strong>.
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Studies of ultra high temperature ceramic composite components : synthesis and characterization of HfOxCy and Si oxidation in atomic oyxgen containing environmentsGeorge, Mekha Raichie. January 1900 (has links)
Thesis (Ph. D. in Chemical Engineering)--Vanderbilt University, Aug. 2008. / Title from title screen. Includes bibliographical references.
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A study on the material and device characteristics of hafnium oxynitride MOSFETs with TaN gate electrodesKang, Changseok, Lee, Jack Chung-Yeung, January 2004 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Jack C. Lee. Vita. Includes bibliographical references. Also available from UMI.
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Processing and reliability studies on hafnium oxide and hafnium silicate for the advanced gate dielectric applicationChoi, Rino, Lee, Jack Chung-Yeung, January 2004 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Jack C. Lee. Vita. Includes bibliographical references.
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Aplicação da espectroscopia de correlação angular perturbada na investigação de interações hiperfinas em compostos de háfnio, indio e cádmio com os ligantes Fsup(1-), OHsup(1-) e EDTA / Application of the perturbed angular correlation in the investigation of hyperfine interactions in compounds of hafnium, indium and cadmium with Fsup(1-), OHsup(1-) and EDTA ligandsAMARAL, ANTONIO A. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:33:45Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:00Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
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