Area-selective formation of an organosilane monolayer on silicon oxide nanopatterns fabricated by scanning probe anodization

An organosilane monolayer was formed from a precursor vapor (trimethylchlorosilane, TMCS) onto the surface of silicon oxide (SiOx) nanopatterns surrounded by hydrogen-terminated silicon (Si–H). The nanopattern was fabricated with a resolution of 20 nm by scanning probe anodization, that is, localized anodization induced beneath the tip of a scanning probe microscope. The area-selectivity arises from the difference in the chemical reactivity of the vapor between the SiOx and Si–H surfaces. The TMCS-coated SiOx patterns showed a resistivity to chemical etching with an aqueous solution of ammonium fluoride and hydrogen peroxide. Lateral force microscopy with an organosilane-coated probe also indicated the presence of the monolayer on SiOx through a friction force contrast between the monolayer-coated and uncoated regions.