Electrode Placement and the Fabrication of Sub-100-nm Nanopore Arrays

Abstract

The anodization of aluminum films grown on silicon substrates under controlled conditions is used to fabricate porous alumina arrays. Such porous arrays are used as sensors or lithography masks for fabrication of sub-100-nm nanodot arrays. The selfassembly of these pores into ordered arrays is determined by anodization parameters. To improve ordering, 2-step anodization can be used. During anodization, the electric field produced by the anodizing electrodes affects pore growth. This field depends on the size and shape of the electrodes as well as the distance between them. It is important that this electric field be properly characterized so that pore development can be better controlled. We model the uniformity of the electric field between the two electrodes using computer simulation. Theoretical dependence of radial and vertical non-uniformity on sample radius and electrode distance is discussed and an optimum electrode geometry is proposed.