Spatially regulated growth of metal oxide thin film onto alkyl monolayer template from aqueous solution containing metal fluoride

We have succeeded in fabricating micropattern of metal oxide thin film from an aqueous solution containing metal fluoride precursor utilizing alkyl monolayer template. Two kinds of monolayers, such as octadecyltrimethoxysilane (OTS) and 1-octadecene (OD), were selected as the starting precursors to be formed onto $SiO2/Si$ and Si surfaces, respectively. Both monolayer templates were prepared by vacuum ultraviolet irradiation through a photomask. The Sn-based thin films were deposited onto both monolayer templates by immersing both monolayer template substrates into an aqueous solution containing 0.03 mol/l of $SnF2$ at $60 °C.$ The micropatterned Sn-based thin films were obtained on both templates after liftoff processing in an anhydrous toluene, respectively. The Sn-based thin film remained site-selectively only on the Si–O area of the OD monolayer template, while it was perfectly peeled off from the methyl-terminated area of the OD monolayer template. The x-ray photoelectron spectrum showed no Si–O component in the Sn-based thin film deposited on Si–O area of the OD monolayer template. On the other hand, the film deposited on the methyl-terminated area of OTS monolayer template could be imperfectly peeled off. Therefore, high-resolution micropattern of the film could not be obtained on the OTS monolayer template. Such different liftoff phenomena were discussed from the viewpoint of different bonding states between each template and the substrates.