Selective Growth of Cu Nanowires on Si(111) Substrates

We succeeded in the fabrication of high-aspect-ratio (length to width) Cu nanowires of less than 10 nm width and 0.5 nm height along atomic step edge lines on Si(111) substrate. The fabrication procedure consisted of two wet process steps: (1) flattening of the surface roughness to an atomic level by immersing Si(111) wafers in ultralow-dissolved-oxygen water (LOW) and (2) Cu nanowire formation by immersion in LOW containing 100 ppb Cu ions for 100 s at room temperature. The selective growth of the Cu nanowires at the step edges indicates that Cu adsorption sites could be formed there during the flattening stage.