Thesis (M. S.)--Nuclear and Radiological Engineering, Georgia Institute of Technology, 2006. / Dr. Cassiano de Oliveira, Committee Member ; Dr. John Mandrekas, Committee Member ; Dr. Weston M. Stacey, Committee Chair. Includes bibliographical references.

Thesis (M.S.)--U.S. Naval Postgraduate School, 1960. / "Controlled Thermonuclear Processes, UC-20" -t.p. "TID-4500 (15th Ed.)" -t.p. Includes bibliographical references (p. 26-27).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. Description based on print version record. Includes bibliographies.

Thesis (Ph. D.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains v, 152 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (p. 129-132).

Augsburg, Univ., Diss., 2008.

Thesis (Ph. D.)--University of Florida, 1982. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 72-74).

Resumo: Esta dissertação de mestrado trata do estudo da caracterização estrutural, e de propriedades óticas e mecânicas do dietilenoglicoldimetiléter (DIGLIME) polimerizado via plasma. Este tipo de plasma produz filmes poliméricos com características físicas, químicas e biológicas semelhantes àquelas observadas em poli(óxido de etileno)- (PEO) e polietileno-glicol (PEG), que são polímeros produzidos através de processos químicos convencionais. Os polímeros a plasma foram obtidos usando descargas de rádio-freqüência operando em 13,56 MHz. Os parâmetros do processos de deposição utilizados foram potência de 10 a 40W e pressão de operação de 120 a 440 mTorr. A estrutura molecular dos polímeros foi estudada por espectroscopia infravermelha. De acordo com os resultados obtidos, baixas pressões e potências de RF produzem filmes poliméricos com características tipo PEO. A tensão mecânica residual nos filmes poliméricos foi investigada pelo método da deflexão de um feixe de laser. Os resultados indicaram tensões compressivas em todos os polímeros e boa estabilidade em função do tempo de envelhecimento. As propriedades óticas dos polímeros a plasma, como coeficiente de absorção, gap ótico e índice de refração foram investigadas através de espectroscopia ultravioleta-visível. O índice de refração calculado é próximo de 1,5 e o gap ótico decresce de 5,0 para 3,5 eV quando a potência de rádio-freqüência é aumentada de 10 para 40W . / Abstract:This Mastering Dissertation deals with the study of structural characterization mechanical and optical properties of the diethyleneglycoldimethylether (diglime) polymerized by plasma. This kind of plasma produces polymer films with interesting physical, chemical and biological characteristics likely those observed in polyethylene-oxide (PEO) and polyethylene-glycol (PEG) that are polymers produced by conventional chemical processes. The plasma polymer films were obtained using 13.56 MHz radio-frequency discharges. The process parameters were RF power from 10 to 40W and operation pressure from 120 to 440 mTorr. The molecular structure of the films was investigate by infrared spectroscopy. According to the obtained results, low pressures and RF power discharges, produce polymer films with PEO-like characteristics. The residual mechanical stress in the films was investigated by the laser beam deflection method. The results indicated compressive stresses in all films and good stability as a time function. The optical properties of the plasma polymers such as absorption coefficient, optical gap and refractive index were investigated using ultraviolet-visible spectroscopy. The calculated refractive index is near 1.5 and the optical gap decreases from 5.0 to 3.3 eV as the RF power is increased from 10 to 40W. / Orientador: Rogerio Pinto Mota / Coorientador: Nilson Cristino da Cruz / Banca: Elson de Campos / Banca: Munemasa Machida / Mestre

Dans les technologies CMOS sur substrat FDSOI, la consommation de silicium dans les zones sources/drains des transistors par les étapes successives de gravure est un paramètre critique. La gravure plasma des espaceurs de Si3N4, qui a lieu après la gravure de la grille, doit permettre la fabrication d'espaceurs au profil droit déterminant la longueur effective du canal sous la grille tout en minimisant la consommation de la couche mince de silicium sous-jacente. De plus, l'état de surface du silicium généré par la gravure des espaceurs ne doit pas entraver la croissance de silicium par épitaxie nécessaire à la fabrication des zones sources/drains surélevées.L'étude des procédés actuels de gravure des espaceurs basés sur des chimies CHxFy/O2 nous apprend que le silicium est consommé par oxydation lors de l'atterrissage du plasma sur le silicium. De plus, l'analyse XPS montre que du carbone est implanté par les ions du plasma dans le substrat de silicium, et celui-ci empêche la recroissance de silicium par épitaxie. Nous sommes en mesure de réduire cette concentration de carbone sans pour autant augmenter la consommation de silicium par l'utilisation de post-traitements plasmas non-oxydants à base d'hydrogène.Fort de cette analyse mettant en avant les limitations des procédés actuels, nous avons développé et caractérisé des procédés de gravure des espaceurs de Si3N4 utilisant des plasmas CH3F/O2/He pulsés synchronisés. La modulation en impulsions courtes avec de faibles rapports cycliques diminue la dose d'ions énergétique reçue par le substrat, ce qui permet de réduire l'épaisseur de silicium oxydé ainsi que la concentration de carbone implanté. L'ajout dans le plasma d'un gaz contenant du silicium, le SiCl4 ou le SiF4, entraine également une réduction de la consommation de silicium grâce au dépôt d'une couche SiOxFy par les radicaux de la phase gazeuse. Le meilleur résultat est obtenu avec un plasma CH3F/O2/He pulsé à 1kHz et 10% de rapport cyclique auquel sont ajoutés 5 ou 10 sccm de SiF4 : la consommation de silicium est alors quasi nulle.Une méthode de gravure alternative basée sur l'implantation d'ions He+ et H+ suivie d'une gravure humide dans une solution HF a également été développée et évaluée pour la gravure des espaceurs de Si3N4. Ce procédé de gravure novateur ne génère aucune consommation de silicium et présente des résultats très prometteurs. / In CMOS technologies on FDSOI substrate, the silicon recess in transistor's source/drain regions caused by multiple etch steps is a critical parameter. The plasma etching of Si3N4 spacers, which occurs after the gate etch step, must allow the fabrication of straight spacer profiles which will define the effective channel length under the gate, while minimizing the consumption of the underlying silicon thin film. Moreover, the silicon surface state generated by the spacers etching must not prevent the epitaxial silicon growth used for the realization of raised source/drain regions.The study of current spacers etch processes based on CHxFy/O2 chemistries shows that silicon is consummated by oxidation when the plasma lands on the silicon surface. Furthermore, the XPS analysis shows that carbon is implanted in the silicon substrate by plasma ions, and that it inhibits the silicon epitaxial regrowth. We are able to reduce the implanted carbon concentration without any additional silicon recess by using non-oxidizing plasma post-treatments based on hydrogen.After identifying the limitations of current etch processes, we developed and characterized Si3N4 spacers etch processes using synchronously pulsed CH3F/O2/He plasmas. The modulation in short pulses with low duty cycles decreases the dose of high energy ions bombarding the substrate, which allows to reduce the oxidized silicon thickness as well as the concentration of implanted carbon. The addition in the plasma of a Si-containing gas, SiCl4 or SiF4, also leads to a reduction of the silicon consumption thanks to the deposition of a SiOxFy layer by radicals from the gas phase. The best result is obtained with a CH3F/O2/He plasmas pulsed at 1 kHz and 10% duty cycle with the addition of 5 or 10 sccm of SiF4 : the silicon recess is then almost zero.We also developed and evaluated an alternative etching technique, based on the implantation of He+ and H+ ions followed by a HF wet etch, for the etching of Si3N4 spacers. This innovative etch process does not generate any silicon recess and shows some promising results.