Utilization of Si atomic steps for Cu nanowire fabrication

Techniques for controlling atomic step position at low-temperature and selective growth of Cu nanowires along the atomic step edges have been studied. By immersing the Si(111) substrates with well-defined step/terrace surfaces in the Cu-contained water with the dissolved oxygen content of less than 1 ppb, selective growth of Cu nanowires along the step edges was successfully achieved. Total reflection X-ray fluorescence spectroscopy (TXRF) revealed that the fabricated nanowires were composed of mono-atomic Cu rows. For step position control, the characteristics of step-flow pinning effect of SiO2 films were investigated. Fine SiO2 line patterns drawn by anodic oxidation using AFM probes enable us to obtain the step-free Si areas predetermined by the patterns.