Caracterização ótica in-situ de filmes finos de a-C:H depositados por plasmas.

• Ano de defesa: 2010
• Autor(a) principal: Pereira, Fabiano Pinto
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Programa de Pós-graduação em Física; Física
• Palavras-chave em Português: Filmes de a-C:H; Caracterização ótica; Reflectometria a laser; Constantes ópticas; Deposição por plasma; Erosão por plasma; PECVD; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: https://app.uff.br/riuff/handle/1/19626

In this work we report the in-situ optical characterization of plasma-deposited a-C:H films, from near-normal reflectance at 633 nm wavelength. The films were deposited by radio frequency Plasma Enhances Chemical Vapor Deposition (rf-PECVD), onto Si (100) single crystalline substrates, placed on a water-cooled cathode, which was capacitively-coupled to a rf (13.56 MHz) power supply. The optical constants, and growth or erosion rates of a-C:H films were determined during deposition experiments in methane plasma, or erosion by N2−H2 mixture plasmas. It was obtained an excellent agreement between the values of the optical constants obtained during growth and erosion of the a-C:H thin films, as well as for the growth and erosion rate. This results show that the optical characterization of a-C:H thin films whose deposition cannot be followed by near normal reflectometry; like hollow-cathode PECVD, can be done by ex-situ erosion experiments. We present a framework for the characterization of plasma deposited a-C:H films from their optical constants n and k, determined at 633 nm wave- lenght. The framework is based on the determination of the volume fractions of diamond-like, polymer-like and graphite-like phases, which are extracted from the optical constants of the studied films, by using a three components effective medium theory, ellecting three standard materials for each one of this phases. The dilution effects of the precursor methane atmosphere by hydrogen gas on the optical constants of a-C:H films were studied. The films was deposited by rf-PECVD and the deposition parameters was similar to the nearfrictionless carbon films.