Etching fabrication of silicon nanostructures using deposited metal clusters as formation nuclei

Abstract

Clusters of Au and Ag deposited on Si substrates were used as nuclei for self-formation of etching masks during electron cyclotron resonance plasma etching with SF 6 gas. As a result, Si pillars ~0.1 μm high were formed with a uniform diameter. The formation mechanism is concluded to be condensation of the reaction product of the etching gas S x F y , preferentially around the deposited clusters, forming etching masks when the substrate temperature was kept at − 130 °C, Au clusters yielded the average pillar diameter of 9 nm, while Ag clusters yielded a 16 nm diameter, indicating that the reactivity of the clusters with the reaction products plays a decisive role in the mask formation. In contrast, experiments using the deposition of size-selected Ag cluster ions indicate that the pillar diameter is almost independent of the cluster size. This feature is particularly advantageous in that equal size pillars can be fabricated without the need for an accurate control of the cluster size.