Site-Selective Deposition of TiO_2 Thin Films Using Self-Assembled Monolayers and Their Dielectric Properties

摘要

TiO_2 thin films were grown on several kinds of SAMs (self-assembled monolayers) using TC (titanium tetrachloride), TDD (titanium dichloride diethoxide) or TE (titanium tetraethoxide) as a starring material. We attempted to improve the feature edge acuity through controlling the reactivity by changing starting materials and surface functional groups of SAMs. The deposition of TiO_2 from TC or TDD solution was promoted on the silanol group, and the deposition was suppressed on OTS (octadecyltrichloro-silane)-SAM. On the other hand, TiO_2 was deposited from TE solution regardless of the type of a surface functional group in the whole area of patterned SAMs. The silanol group which has high hydrophilicity accelerated the growth of TiO_2, but the OTS-SAM which has hydrophobicity suppressed the growth of TiO_2. It is also clarified that the chlorine atom in starting material has high reactivity with silanol groups of SAMs. As-deposited thin films were amorphous with different compositions depending on the starting material and crystallized into anatase by annealing above approx 300 DEG C. Current-voltage characteristics of a MOS device constructed from TiO_2 thin film was evaluated.