Fabrication of size-controlled 10-nm scale Si pillars using metal clusters as formation nuclei

10-nm scale Si pillars were fabricated using deposited Au, Ag, Cu clusters and colloidal Au particles as nuclei for formation of etch masks in SF, microwave plasma etching at about -130 degrees C. The pillar diameter is affected by the chemical species of the clusters, but is only weakly dependent on the cluster size. The average diameter of pillars fabricated with Au clusters is 9 nm, while those with Ag and Cu clusters are 19 and 24 nm, respectively. This is considered to be due to the difference in stability of the compounds of Au, Ag, and Cu with S or F, the components of the etching gas, which results in a different ability to form etch masks by condensation of SxFy species.