Self-assembled monolayers (SAMs) bearing sulfonate (-SO3H) surface functional groups, on single-crystal Si wafers, were used as substrates for the deposition of TiO2 thin films from aqueous solutions. Polycrystalline TiO2 thin films over 50 nm thick formed in 2 h by hydrolysis of TiCl4 in aqueous HCI solutions at 80 °C. The films were pore-free, showed excellent adherence and uniformity, and consisted of anatase crystallites 2–4 nm in diameter. Annealing at temperatures up to 600 °C caused coarsening of the anatase grains, but no loss of adherence or structural integrity.

Patterned thin films of TiO2 were deposited from aqueous solution onto photopatterned self-assembled monolayer (SAM) films on Si substrates. Regions of the SAM containing sulfonate surface functionality were created by the photo-oxidation of initially deposited thioacetate groups through a mask. The nanocrystalline TiO2-on-SAM films were deposited selectively on the photolyzed regions of the SAM. The electrical properties of such films were assessed for potential microelectronic device applications. Current–voltage and capacitance–voltage measurements made on nonpatterned TiO2 films yielded values of relative permittivity ranging from 24 to 57, film resistivities of 1.0–1.5×109 Ω cm and breakdown voltages in excess of 1 MV/cm.

Functionalized, siloxane-anchored, self-assembled monolayers (SAMs) have been shown to provide uniform, stable,

Crystalline, uniform, adherent, ultrathin films of TiO2 were deposited onto OH-functionalized organic self-assembled monolayers (SAMs) on single-crystalline Si at low-temperature (<100 °C) from anhydrous ethanolic solutions of titanium isopropoxide. The films were identified as TiO2 by x-ray photoelectron spectroscopy, electron diffraction, and energy-dispersive x-ray microanalysis. Transmission electron microscopy showed the films to be uniform in thickness (2 ± 0.5 nm) and continuous. On bare Si, in contrast, there was no evidence of TiO2 deposition under identical conditions. Unlike the anatase films deposited on SAMs from aqueous solutions (described in the preceding paper), the electron diffraction patterns of the films deposited from alkoxide solutions suggest that they were the rutile phase. It is suggested that the functionalized SAMs enable the anchoring of the Ti alkoxide and initiate the formation of an adherent oxide film, and that they are sufficiently uniform that the resulting film is continuous and uniform in thickness.