Controlled thin film etching is essential for future semiconductor devices, especially with complex high aspect ratio structures. Therefore, self-limiting atomic layer etching processes are of great interest to the semiconductor industry. In this work, a process for atomic layer etching of aluminum oxide (Al2O3) films using sequential and self-limiting thermal reactions with trimethylaluminum and hydrogen fluoride as reactants was demonstrated. The Al2O3 films were grown by atomic layer deposition using trimethylaluminum and water. The cycle-by-cycle etching was monitored throughout the entire atomic layer etching process time using in situ and in real-time spectroscopic ellipsometry. The studies revealed that the sequential surface reactions were self-limiting versus reactant exposure. Spectroscopic ellipsometry analysis also confirmed the linear removal of Al2O3. Various process pressures ranging from 50 to 200 Pa were employed for Al2O3 etching. The Al2O3 etch rates increased with process pressures: Al2O3 etch rates of 0.92, 1.14, 1.22, and 1.31 Å/cycle were obtained at 300 °C for process pressures of 50, 100, 150, and 200 Pa, respectively. The Al2O3 etch rates increased with the temperature from 0.55 Å/cycle at 250 °C to 1.38 Å/cycle at 350 °C. Furthermore, this paper examined the temperature dependence of the rivalry between the removal (Al2O3 etching) and growth (AlF3 deposition) processes using the reactants trimethylaluminum and hydrogen fluoride. The authors determined that 225 °C is the transition temperature between AlF3 atomic layer deposition and Al2O3 atomic layer etching. The high sensitivity of in vacuo x-ray photoelectron spectroscopy allowed the investigation of the interface reactions for a single etching pulse as well as the initial etch mechanism. The x-ray photoelectron spectroscopy measurements indicated that the fluorinated layer is not completely removed after each trimethylaluminum exposure. The Al2O3 atomic layer etching process mechanism may also be applicable to etch other materials such as HfO2.

Orientador: Francisco Elinaldo Teixeira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Artes / Made available in DSpace on 2018-08-27T09:40:46Z (GMT). No. of bitstreams: 1 Rios_EdnaMaria_M.pdf: 1169066 bytes, checksum: 9f2ceefed4050cc633a6ae7802e6de8a (MD5) Previous issue date: 2015 / Resumo: A presente dissertação, apropria-se da experiência audiovisual do dispositivo-jantar como objeto de reflexão, perpassa as seis cerimônias realizadas entre as cidades de Salvador e São Paulo, e encontra, nos rituais instalados em situação de rua, a possibilidade tanto de situar-se no devir criativo do projeto aqui esboçado: Entre ruas e calçadas, como de penetrar diferentes territórios audiovisuais com montagens e apropriações de sua malha imagética. O que o presente texto oferece é o sopro de uma criação que tem a incompletude como condição, a incerteza como única certeza. Em seu começo, uma disposição primeira: a cerimônia do jantar. Em seu percurso, a escultura de uma força criativa que se fez e refez no encontro com seus intercessores. Da inoperância temática, a abertura de possibilidades de seu dispositivo de escritura em diferentes montagens, por entre diferentes domínios do audiovisual / Abstract: This present work is resulted by the reflection about the audiovisual experience acquired from using the dinner ritual as a dispositif. It passes through six dinner rituals that took place in São Paulo and Salvador, two of which being done in the street with homeless people. These two particular dinners opened the possibility to go through a more creative path, here drawn by the Entre ruas e calçadas project, or to get into other audiovisual territories with different settings and different uses of its imagetic grid. This text offers a glimpse of a creation having the incompleteness as a condition, the uncertainty as the only assurance. When the project began, there was just one thought: the dinner ritual. During its course: the sculpture of a creative strength that elaborates and re-elaborates itself while understands its intermediators; of its thematic ineffectiveness: the possibilities opened to fit the installation dispositif to other different settings and different audiovisual domains / Mestrado / Multimeios / Mestra em Multimeios