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I propose to develop a new method for the synthesis of metal matrix composites (MMC) using aerosol reactants in a radio frequency (RF) plasma torch. An inductivelycoupled RF plasma torch (ICPT) may potentially be designed to maintain laminar flow and a radial temperature distribution. These two properties provide a method by which a succession of metal layers can be applied to the surface of SiC fibers. In particular, the envisaged method provides a means to fully bond any desired metal to the surface of the SiC fibers, opening the possibility for MMCs in which the matrix metal is a highstrength steel. A crucial first step in creating the MMC is to test the feasibility of constructing an ICPT with completely laminar flow in the plasma region. In this work, a magnetohydrodynamic (MHD) model is used along with a computational fluid dynamic (CFD) software package called FLUENT© to simulate an ICPT. To solve the electromagnetic equations and incorporate forces and resistive heating, several userdefined functions (UDF) were written to add to the functionality of FLUENT©. Initially, an azimuthally-symmetric, two-dimensional model was created to set a test baseline for operating in FLUENT© and to verify the UDF. To incorporate coil angle and current leads, a fully three dimensional model UDF was written. Preliminary results confirm the functionality of the code. Additionally, the results reveal a non-mixing, laminar flow outer region for an axis-symmetric ICPT.

The plasma-based etching processes of copper (Cu) and titanium tungsten (TiW) thin films, and the electromigration of the copper lines patterned by above etching processes were studied. Instead of vaporizing the plasma/copper reaction product, a dilute hydrogen chloride solution was used to dissolve the nonvolatile reaction product. The plasma/copper reaction process was affected by many factors including the microstructure of the copper film and the plasma conditions. Under the same chlorine plasma exposure condition, the copper conversation rate and the copper chloride (CuClx) formation rate increased monotonically with the Cu grain size. The characteristics of the Cu etching process were explained by diffusion mechanisms of Cl and Cu in the plasmacopper reaction process as well as microstructures of Cu and CuClx. The Cu chlorination process was also affected by the additive gas in the Cl2 plasma. The additive gas, such as Ar, N2, and CF4, dramatically changed the plasma phase chemistry, i.e., the Cl concentration, and the ion bombardment energy, which resulted in changes of the Cu chlorination rate and the sidewall roughness. TiW thin films, used as the diffusion barrier layer for the Cu film, were reactive ion etched with CF4/O2, CF4/Cl2, and CF4/HCl plasma. Process parameter such as feed gas composition, RF power, and plasma pressure showed tremendous effects on the etch rate and the etch selectivity. The TiW etch rate was a function of the sum of Cl and F concentrations and the ion bombardment energy. Cu/diffusion barrier metal stack was successfully patterned by above plasma etch processes. The electromigration (EM) performance of the Cu lines was evaluated by the accelerated isothermal test. The activation energy of 0.5~0.6 eV and the current density exponent of 2.7 were obtained. Failure analysis showed that both copper-silicon nitride cap layer interface and the copper grain boundary were active diffusion paths. The EM induced stress caused the cap layer crack and affected the reliability of Cu lines. The processes studied in this dissertation can be applied in advanced microelectronic fabrication including large area flexible microelectronics.

The attenuated total reflection (ATR) method and the scattering spectrum analysis are used to study the effects due to the surface plasma of Ag nanoparticles. A slide is coated with a thin Ag film of thickness about 40nm and anneals the sample few minutes at 197¢XC. The Ag film is thus congregated to be a rough surface. By ATR(with the slide attached to the back of the prism), the intensity of the total refection light and the reflective angle are measured. Then we can determine the dielectric coefficient of the rough Ag surface. We also coat a thin Ag film about 8nm on the ITO glass and anneal the sample. The thin Ag film is thus congregated to be nanoparticles. We discuss the effects due to the surface plasma excited on the Ag nanoparticles by analyzing the absorbance and scattering spectrums from Ag nanoparticles in liquid crystals environment.

Abstract In this study, we use a fisheye lens (180o field of view) and Chare-Couple Device to take the all-sky 6300Å airglow images emitting from ionosphere. By analyzing these Images we can study the phenomenon of equatorial plasma depletions (plasma bubble). Plasma bubbles generate above the magnetic equator; and they drift up to higher altitude and spread to higher latitude area along magnetic lines. The all-sky imaging system was operated at Mt. A-Li (23.511oN, 120.823oE). Because this year is the most active time of sunspots in the solar cycle, we expect that we can take mounts of plasma bubble images in this year.

Application of surface wave plasma technology for effective abatement of environmentally harmful gases such as perfluorocompounds and chlorofluorocarbons is investigated. Perfluorocompounds (PFCs) are gases that contribute to forced global warming and have been favored for wafer etch and chamber clean applications in the semiconductor industry. Chlorofluorocarbons (CFCs) are ozone depleting gases that were used as refrigerants for commercial and domestic condensers and air conditioners, but current reserves still pose threats to environmental sustainability. Increased average global temperatures and further destruction of the ozone layer have prompted proposal of international initiatives such as the Montreal Protocols and the Kyoto Agreement to curtail emissions of such fugitive gases into the environment. These have increased the need for effective abatement technologies to control such emissions and include surface wave plasma abatement, the subject of this dissertation. Surface wave plasmas are considered high frequency non-equilibrium traveling wave discharges in contrast to the more frequently used standing wave discharges. The use of surface wave plasmas have the advantages of a variety of discharge vessel shapes, reproducibility of application, numerous operating conditions and large plasma volumes which ultimately produce low, molecular weight byproducts that are associated with high effective electron temperatures but low heavy particle temperatures. For these reasons, surface wave plasma abatement technology was developed for the destruction and removal of PFCs and CFCs. Results include final destruction and removal efficiencies (DREs) for octafluorocyclobutane greater than 99.8%, dichlorodifluoromethane greater than 99.995% and trichlorofluoromethane greater than 99.999% using moderate applied microwave powers of less than 2000 watts with the production of low molecular weight byproducts, such as CO2, CO, HF and HCl, that prevent environmentally harmful process emissions from entering the atmosphere. Characterizations of the initial and final products were accomplished by the use of Fourier transform infrared spectroscopy and quadrupole mass spectrometry to provide independent quantitative analyses of plasma processes. In addition to these analytical methods, Global_Kin a kinetic model, of plasma reactions were conducted and compared to all the experimental data determined in order to facilitate understanding of the chemistry involved in the surface wave plasma abatement applications studied. Basic plasma reaction mechanisms were determined for the abatement of octafluorocyclobutane and dichlorodifluoromethane.

Thesis (Ph. D.)--Open University.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.

Thesis (M.S. in M.S.E.)--School of Materials Science and Engineering, Georgia Institute of Technology, 2004. Directed by Christopher J. Summers. / Includes bibliographical references (leaves 148-152).

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 53-56). Available also in a digital version from Dissertation Abstracts.