The equivalent impedance of a RF plasma was experimentally determined by monitoring the voltage and current waveform for different input powers in real time. Average ion energies and fluxes were determined by a computer model which takes ion collisions in the sheath regions into account. In addition two models were proposed which explain how RF energy is converted to DC potential energy in the sheath. Etch rates of Si in a CF₄ discharge were also evaluated and related to the measurements.

A study of potentiostatic and galvanostatic electrochemical etching of silicon in tetramethylammonium hydroxide (TMAH) has been carried out. In TMAH baths,, we find that biased (100) silicon etch rates increase 21% over OCP etch rates. For TMAH baths seasoned with silicon, biased silicon etch rates increase to 63% over those at OCP. Electrochemical etching eliminates the growth of hillocks on etching surfaces regardless of etchant pH, [TMAH] or silicon loading, resulting in highly smooth etching surfaces. Potentiostatic and galvanic etching yield similar etch rates and surface consistency. / Graduation date: 2003

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Thesis (M.A. (Art History)) -- University of Adelaide, 2002. / Bibliography: leaf 83-86.

A selective sloped silicon dioxide etching method has been studied using a temperature controlled diode-type reactive ion etch system with CHCl₃, C₂F₆, H₂ and N₂ gases. The SiO₂ was covered by a polyimide mask with vertical sidewalls and window openings from 1.25-4 microns. Control of the sidewall slope in SiO₂ is possible through varying the ratios of CHCl₃ and C₂F₆. High percentages (95-100%) of CHCl₃ resulted in low etch rates of 420 angstroms/min. Large slopes of up to 65 degrees are possible. With C₂F₆ above 5%, larger etch rates close to 2000 angstroms/min. occur and etching becomes vertical with purely anisotropic profiles at 10% C₂F₆. In a simulation study, SiO₂ sidewall slope was found to be controlled by the isotropic deposition rate as well as the anisotropic etch rate. Optical Multichannel Analysis of the discharge showed an increase in silicon dioxide removal when the percentage of C₂F₆ was increased. (Abstract shortened with permission of author.)

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Graduation date: 2005

Graduation date: 1999