Various physical parameters of solvents within two component, PMMA + Solvent films are analyzed for their impact upon the coating uniformity of spin deposited PMMA films. Towards this end, a model is presented for describing the surface behavior of spin-on films during the latter stages of deposition, correlating the tendency of a film toward non-uniform deposition to physical characteristics of the spin-on solution. A finite difference solution to this model is presented for two-component, spin-on films that is shown to effectively predict the uniformity of the resulting thin-film layers. The model is then used to determine the impact of specific film parameters upon the predicted spin-on uniformity of the film. Based upon these results, the interdependency between evaporation rate, solvent viscosity, surface tension and rotation rate in determining the uniformity of the spin-on film is evaluated by comparing the model predictions against those found in actual spin-on, two component films. The results from this model are used to provide a physical explanation for why certain surface non-uniformities begin to develop during spin coating.

Metal-oxide thin films are used in a wide variety of electronic devices. Although many techniques have been developed to deposit thin films of metal oxides, there is still a need for alternative cost- and energy-effective deposition methods. Deposition of metal oxide thin films from aqueous solutions of all-inorganic metal salts is a viable method that meets these needs. Although many aqueous-deposited metal-oxide thin films have been successfully incorporated into functioning devices, many of the mechanisms that occur as precursors transition to metal oxides are not well understood. The work presented in this dissertation is primarily concerned with examining the processes that occur as metal oxide thin films form from spin-deposited aqueous precursor solutions with a particular focus on the role of H2O in these processes. Chapter I summarizes methods for thin film deposition, and describes the use of aqueous metal salt solutions as viable precursors for the deposition of metal oxide thin films. Chapter II investigates the precursor chemistry, film-formation processes and properties of LaAlO3 thin films deposited from aqueous precursors. This chapter also serves as general guide to the processes that occur as metal-oxide thin films form from spin-deposited aqueous precursors. Chapters III and IV focus on the effects of H2O(g) during spin-deposition of precursor thin films and during the annealing process in which precursors are converted to metal oxides, respectively. The presence of H2O(g) during spin-deposition has a striking effect on the thickness of the resulting thin films and also affects the elemental gradient and density profiles. During annealing, H2O(g) reduces the temperatures at which counterions are expelled and influences the metal-hydroxide framework formation and its condensation to a metal oxide. The data also indicate that H2O(g) enhances diffusion of gaseous byproducts from within the films. Chapter V focuses on precursor concentration and its impact on the thermal evolution of thin films. The processes involved in the conversion of precursors to metal oxide thin films occur at lower temperatures as precursor concentration decreases. Although this is likely in part due to thickness effects, concentration-dependent precursor speciation may also be involved in lowering the temperatures at which films densify. / 2019-02-17