Corrosão anisotropica e formação de superficie nanoestruturada de Si utilizando plasma de alta densidade / Si anisotropic etching and nanostructured surface formation using high density plasma

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

29/07/2009

RESUMO

This work explores the implementation, characterization and applications of BOSCH type process for bulk silicon etching (or bulk silicon micromachining) using inductively coupled high density plasma (ICP). This etching process is characterized by its high anisotropy and is performed by alternating etching steps, employing SF6 + Ar gas mixture, and passivation steps, employing C4F8 + Ar gas mixture. Ni-P metallic masks grown by electroless over silicon substrate were employed, showing high selectivity and thus allowing for long process times for deep etching. The difficulties of process implementation are discussed and a method to implement it is shown, comprising plasma etching with SF6 + Ar and fluorocarbon polimer deposition with C4F8 + Ar plasma. With a BOSCH type process developed, some experiments were performed aiming to optimize the anisotropy and the etch rate, the effect of process parameters on etching profiles was discussed. Medium etching rates of about 1.5 µm/min and vertical walls were achieved. The applications of this process include: (1) fabrication of a pressure sensor membrane and (2) fabrication of nanostructured silicon surfaces like nanopillars and nanocones. The nanocones surfaces are characterized by high light absorption ("black silicon") presenting minimum diffuse relectance of 0.91% at l = 783 nm, being potentially of great interest for photovoltaic convertion

ASSUNTO(S)

silicio microeletronica detectores corrosão silicon microelectronics sensors corrosion

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