Técnica híbrida de plasma para a deposição de filmes de alumina

• Ano de defesa: 2015
• Autor(a) principal: Prado, Eduardo Silva [UNESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Filmes finos; Alumina; Topografia; Análise espectral; Thin films
• Link de acesso: http://hdl.handle.net/11449/132495; http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/14-12-2015/000855048.pdf

A new plasma methodology for deposition of alumina from aluminum acetylacetonate, AAA, is proposed. In a previous study by his this group, the possibility of depositing films from the AAA, by sputtering in argon atmosphere. In the present work, this methodology was modified by coupling a bombardment to the deposition process. For this, the plasma was generated by the application of radifrequency signal (13.56 MHz) to the lowermost electrode of a capacitively coupled plasma system with the AAA powder was spread. The topmost electrode, also used as the sample holder, was biased with retangular negative pulses of controlled amplitude, frequency and duty cycle. Sputtering of AAA fragments by the argon plasma provides precursors for film deposition while the polarization of the holder accelerates ions toward the substrates, promoting ion bombardment of the growing layer. The plasma excitation parameters (11 Pa, 13.56 MHz, 150 W, 3600 s) were the same as those optimized in the previous work of the group. The magnitude of the pulses was varied from 0 to 2800 V. To change the energy delivered by ion bombardment to the structure. A fixed pulse frequency and duty cycle were fixed of 300 Hz and duty cicle changed between (0 and 100%). The effect of P on the film properties was investigated. Deposition rates were determined from the deposition time and film thinckness, measured by profilometry. Infrared spectroscopy in the IRRAS mode (InfraRed Reflectante Absorbance Spectroscopy) was used to investigate the molecular structure of the layers. X-ray diffractometry was employed to verify if there was precipitation of crystalline alumina phases. The material microstructure was investigated by scanning electron and atomic force microscopies. Elemental composition analyses were performed by Energy Dispersive Spectroscopy while data obtained by nanoindentation tests allowed the calculation of hardness. The structures present (C-H, C=O, C=C e (C-H)3 organic...