Fabrication of an ordered anodic aluminum oxide pore arrays with an interpore distance smaller than the nano-indentation pitch formed by ion beam etching

We investigated a method for preparation of self-ordering nanopore arrays with the interpore distance of 60 nm by guided self-organization of anodic aluminum oxide (AAO) with a pre-patterned ordered array of indentations of Al film. An ordered triangular array of 100 nm-pitch indentations was formed on Al film by ion beam etching (IBE) with the EB resist mask, and then it was used as a guide for formation of AAO pore. We found it was possible to reduce an interpore distance of AAO to 1/√3 of the pitch of the indentation by the choice of appropriate IBE parameters and anodization voltage.