Regensburg 2007 – scientific programme

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DS: Fachverband Dünne Schichten

DS 15: Poster Session

DS 15.48: Poster

Tuesday, March 27, 2007, 15:00–17:00, Poster B

Functional oxide films patterned by soft-lithography — •Ole Fridthjof Göbel, Sajid Ullah Khan, Johan Evert ten Elshof, and David Hermanus Adrianus Blank — Inorganic Materials Science Group, University of Twente, the Netherlands

Soft-lithographic techniques, e.g. micromoulding in capillaries (MIMIC), have been applied to relief-pattern sol-gel precursor solutions for functional oxides such as TiO₂, BaTiO₃, or CoFe₂O₄. Subsequent heat treatment yields patterned oxide films, patterns being parallel lines or grids. The periodicities of the patterns amount typically a few micrometers. Unlike with standard micromoulding, with MIMIC the relief-patterned mould is in contact with the substrate before applying the precursor solution, such that the formation of a thin residue layer between the pattern features is avoided. Since, however, MIMIC is restricted to patterns with interconnected features, inverse MIMIC must be applied to create patterns of isolated features: In a first step, a negative image of the final pattern is created in a fully organic polymer (e.g. poly(urethane)) by MIMIC, yielding a grid-patterned film with pits, the bottom of which is the substrate. In a second step, the isolated pits in the polymer film are filled with the precursor solution. To improve the patterning process in MIMIC, the physical properties of the surfaces of the elastomeric moulds have been modified. Besides sol-gel precursors, also suspensions of TiO₂ nanoparticles have been used to reduce film shrinkage.