Chlorine plasma etching of polysilicon films for MEMS and MOS devices / Corrosão de filmes de silicio policristalino por plasma para aplicações em dispositivos MEMS e MOS utilizando misturas de gases com cloro

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

This work presents the results and the discussion about mechanisms of plasma etching of polysilicon and silicon films for applications in MEMS and MOS devices. The etching was performed in a conventional reactor of plasma etching, Applied Materials PE8300A model, in a RIE mode (Reactive Ion Etching). For application in MEMS, polysilicon etching with anisotropic profile and high selectivity (>20) for silicon oxide was obtained. The mixtures used in etching were SF6/Ar/Cl2 and SF6/Ar/Cl2. The evolution of the etching profile is better evaluated using polysilicon thick films (>2 µm). For application in MOS transistors electrode, 2,5 µm to 500 nm thinning was obtained with anisotropic profile (At~0,95). For surface routh analisys, before and after the etching processes in Ar/SF6 and Ar/SF6/Cl2 plasmas, sub-micrometric polysilicon lines, with platinum mask deposited by FIB, were etched. Next, silicon dioxide etching processes were executed using Ar/SF6 mixtures in order to obtain high etching rates. Finally, photoresist masks were removed without compromising the adjacent material by the use of oxygen. The films were characterized with the use of a variety of equipment. The Profiler was used to measure the etching depth, and therefore the etching rate was evaluated

ASSUNTO(S)

corrosão anisotropy silicio - propriedades eletricas silicion metal oxide semiconductors anisotropia semicondutores de oxido metalico corrosion

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