Large-Scale preparation of uniform nanopatterned silicon substrates by inductively coupled plasma etching using self-assembled anodic alumina masks

Nanopatterned silicon substrate has potential applications in the optoelectronic fields. However, its preparation is often complex and costly. In this paper, self-assembled anodic aluminum oxide (AAO) film masks on silicon substrates were deposited by a simple and feasible method, which was based on the direct anodization of sputtered Al film instead of previous reported Al/SiO₂ or Al/Ti/SiO₂ films. With the as-deposited AAO film masks other than common freestanding AAO templates, nanopatterned silicon substrates were finally obtained using two-step inductively coupled plasma (ICP) etching. The experimental results show that the pore arrangement of the AAO film has been successfully transferred to the silicon substrates after the ICP etching. The average diameter, wall thickness and depth for the as-obtained silicon nanopore arrays are approximately 65 nm, 40 nm, and 260 nm, respectively. It is believed that the above-proposed method has the potential for the fabrication of large-scale and uniform sub-100 nm nanopatterned silicon substrates.