Scanning tunneling microscope tip‐induced anodization of titanium: Characterization of the modified surface and application to the metal resist process for nanolithography

Nanometer scale oxide patterns were fabricated on titanium (Ti) surfaces on the basis of scanning tunneling microscope (STM) tip‐induced anodization. The spatial resolution of the method was limited to approximately 20 nm, owing to the surface roughness of the Ti film used. Chemical analyses of fabricated patterns by Auger electron spectroscopy proved that the surface chemical composition of the pattern was titanium dioxide (TiO2), and the oxide thickness on the pattern was certainly thicker than that of the native oxide on the unmodified area. A novel Ti‐metal resist process for nanolithography based on STM tip‐induced anodization was proposed. The Ti film on which anodized patterns were formed could be etched by hydrofluoric acid using the anodic oxide patterns as an etching mask. Ti lines of ∼60 nm in width were successfully fabricated by the present method.