Electrochemical etching of silicon through anodic porous alumina

Porous silicon with a self-ordered pore configuration having a 100 nm periodicity was fabricated by electrochemical etching of a Si substrate through a nanochannel array of anodic porous alumina. The self-ordered anodic porous alumina used as a mask was directly prepared by anodizing an aluminum film sputtered on a Si substrate. The transfer of the self-ordered nanoporous pattern of anodic alumina onto the Si substrate could be achieved by selective electrochemical etching of exposed silicon, which was located in the pore base of the upper anodic porous alumina. The periodicity of the pore array in Si could be controlled easily by changing the channel interval of anodic porous alumina used as a mask.